Merge pull request #91 from rrthomas/master

Overhaul compiler warning flags

25 files changed, 630 insertions, 232 deletions

diff --git a/.gitignore b/.gitignore
index 4bcf773..3adc1d7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+*~
 *.o
 *.lo
 *.la
diff --git a/bootstrap.conf b/bootstrap.conf
index 3b9b799..de3293e 100644
--- a/bootstrap.conf
+++ b/bootstrap.conf
@@ -1,4 +1,4 @@
-# bootstrap.conf (GNU zile) version 2017-02-10
+# bootstrap.conf (GNU zile) version 2017-02-20
 # Written by Gary V. Vaughan, 2010
 
 # Copyright (C) 2010 Free Software Foundation, Inc.
@@ -47,6 +47,9 @@ gnulib_tool_options='
 gnulib_modules='
         bootstrap
         flock
+	manywarnings
+        manywarnings-cxx
+        snippet/unused-parameter
 '
 
 
diff --git a/configure.ac b/configure.ac
index 93d1357..3d92a6d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -55,129 +55,58 @@ PKG_PROG_PKG_CONFIG
 
 PKG_CHECK_MODULES(GLIB, [glib-2.0 >= 2.6 gmodule-2.0])
 
-dnl ===========================================================================
-dnl check compiler flags
-AC_DEFUN([ENCHANT_CC_TRY_FLAG], [
-  AC_MSG_CHECKING([whether $CC supports $1])
-
-  enchant_save_CFLAGS="$CFLAGS"
-  CFLAGS="$CFLAGS $1"
-
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]])], [enchant_cc_flag=yes], [enchant_cc_flag=no])
-  CFLAGS="$enchant_save_CFLAGS"
-
-  if test "x$enchant_cc_flag" = "xyes"; then
-    ifelse([$2], , :, [$2])
-  else
-    ifelse([$3], , :, [$3])
-  fi
-  AC_MSG_RESULT([$enchant_cc_flag])
-])
-
-dnl check compiler flags
-AC_DEFUN([ENCHANT_CXX_TRY_FLAG], [
-  AC_MSG_CHECKING([whether $CXX supports $1])
-
-  AC_LANG_PUSH(C++)
-  enchant_save_CXXFLAGS="$CXXFLAGS"
-  CXXFLAGS="$CXXFLAGS $1"
-
-  AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[ ]])], [enchant_cxx_flag=yes], [enchant_cxx_flag=no])
-  CXXFLAGS="$enchant_save_CXXFLAGS"
-
-  if test "x$enchant_cxx_flag" = "xyes"; then
-    ifelse([$2], , :, [$2])
-  else
-    ifelse([$3], , :, [$3])
-  fi
-  AC_MSG_RESULT([$enchant_cxx_flag])
-  AC_LANG_POP(C++)
-])
-
-dnl Use lots of warning flags with gcc and compatible compilers
-
-dnl Note: if you change the following variable, the cache is automatically
-dnl skipped and all flags rechecked.  So there's no need to do anything
-dnl else.  If for any reason you need to force a recheck, just change
-dnl MAYBE_WARN in an ignorable way (like adding whitespace)
-
-CC_MAYBE_WARN="-Wall -Wextra \
--Wsign-compare -Werror-implicit-function-declaration \
--Wpointer-arith -Wwrite-strings -Wstrict-prototypes \
--Wmissing-prototypes -Wmissing-declarations -Wnested-externs \
--Wpacked -Wswitch-enum -Wmissing-format-attribute \
--Wstrict-aliasing=2 -Winit-self -Wunsafe-loop-optimizations \
--Wdeclaration-after-statement -Wold-style-definition \
--Wno-missing-field-initializers -Wno-unused-parameter \
--Wno-attributes -Wno-long-long -Winline -fno-strict-aliasing"
-
-# invalidate cached value if MAYBE_WARN has changed
-if test "x$enchant_cv_warn_maybe" != "x$CC_MAYBE_WARN"; then
-	unset enchant_cv_warn_cflags
-fi
-AC_CACHE_CHECK([for supported C warning flags], enchant_cv_warn_cflags, [
-	echo
-	CC_WARN_CFLAGS=""
-
-	# Some warning options are not supported by all versions of
-	# gcc, so test all desired options against the current
-	# compiler.
-	#
-	# Note that there are some order dependencies
-	# here. Specifically, an option that disables a warning will
-	# have no net effect if a later option then enables that
-	# warnings, (perhaps implicitly). So we put some grouped
-	# options (-Wall and -Wextra) up front and the -Wno options
-	# last.
-
-	for W in $CC_MAYBE_WARN; do
-		ENCHANT_CC_TRY_FLAG([$W], [CC_WARN_CFLAGS="$CC_WARN_CFLAGS $W"])
-	done
-
-	enchant_cv_warn_cflags=$CC_WARN_CFLAGS
-	enchant_cv_warn_maybe=$CC_MAYBE_WARN
-
-	AC_MSG_CHECKING([which C warning flags were supported])])
-CC_WARN_CFLAGS="$enchant_cv_warn_cflags"
-AC_SUBST(CC_WARN_CFLAGS)
-
-CXX_MAYBE_WARN="-Wall -Wextra \
--Wsign-compare \
--Wpointer-arith -Wwrite-strings \
--Wpacked -Wswitch-enum -Wmissing-format-attribute \
--Wstrict-aliasing=2 -Winit-self -Wunsafe-loop-optimizations \
--Wno-missing-field-initializers -Wno-unused-parameter \
--Wno-attributes -Wno-long-long -Winline -fno-strict-aliasing"
-
-# invalidate cached value if MAYBE_WARN has changed
-if test "x$enchant_cxx_cv_warn_maybe" != "x$CXX_MAYBE_WARN"; then
-	unset enchant_cxx_cv_warn_cflags
+dnl Extra warnings with GCC and compatible compilers
+AC_ARG_ENABLE([gcc-warnings],
+  [AS_HELP_STRING([--disable-gcc-warnings],
+                  [turn off lots of GCC warnings])],
+  [case $enableval in
+     yes|no) ;;
+     *)      AC_MSG_ERROR([bad value $enableval for gcc-warnings option]) ;;
+   esac
+   gl_gcc_warnings=$enableval],
+  [gl_gcc_warnings=yes]
+)
+if test "$gl_gcc_warnings" = yes; then
+  dnl Set up the list of undesired warnings.
+  nw=
+  nw="$nw -Wsystem-headers"   # Don’t let system headers trigger warnings
+  nw="$nw -Wundef"            # All compiler preprocessors support #if UNDEF
+  nw="$nw -Wtraditional"      # All compilers nowadays support ANSI C
+  nw="$nw -Wdeclaration-after-statement" # We require C99.
+  nw="$nw -Wstrict-overflow"  # Use a lower level (see below).
+  nw="$nw -Wconversion"       # These warnings usually don’t point to mistakes.
+  nw="$nw -Wsign-conversion"  # Likewise.
+
+  gl_MANYWARN_ALL_GCC([warnings])
+
+  dnl Enable all GCC warnings not in this list.
+  gl_MANYWARN_COMPLEMENT([warnings], [$warnings], [$nw])
+  for w in $warnings; do
+    gl_WARN_ADD([$w])
+  done
+
+  gl_MANYWARN_ALL_GXX([cxx_warnings])
+
+  dnl Enable all G++ warnings not in this list.
+  gl_MANYWARN_COMPLEMENT([cxx_warnings], [$cxx_warnings], [$nw])
+  for w in $cxx_warnings; do
+    gl_CXX_WARN_ADD([$w])
+  done
+
+  dnl Add an extra warning
+  gl_WARN_ADD([-Wstrict-overflow=1])
+  dnl Add some more safety measures
+  gl_WARN_ADD([-D_FORTIFY_SOURCE=2])
+  dnl Remove a warning being promoted to error: we trigger this and can't turn it off with pragmas.
+  gl_WARN_ADD([-Wno-error=format-security])
+
+  # When compiling with GCC, prefer -isystem to -I when including system
+  # include files, to avoid generating useless diagnostics for the files.
+  ISYSTEM='-isystem '
+else
+  ISYSTEM='-I'
 fi
-AC_CACHE_CHECK([for supported C++ warning flags], enchant_cxx_cv_warn_cflags, [
-	echo
-	CXX_WARN_CFLAGS=""
-
-	# Some warning options are not supported by all versions of
-	# gcc, so test all desired options against the current
-	# compiler.
-	#
-	# Note that there are some order dependencies
-	# here. Specifically, an option that disables a warning will
-	# have no net effect if a later option then enables that
-	# warnings, (perhaps implicitly). So we put some grouped
-	# options (-Wall and -Wextra) up front and the -Wno options
-	# last.
-
-	for W in $CXX_MAYBE_WARN; do
-		ENCHANT_CXX_TRY_FLAG([$W], [CXX_WARN_CFLAGS="$CXX_WARN_CFLAGS $W"])
-	done
-
-	enchant_cxx_cv_warn_cflags=$CXX_WARN_CFLAGS
-	enchant_cxx_cv_warn_maybe=$CXX_MAYBE_WARN
-
-	AC_MSG_CHECKING([which C++ warning flags were supported])])
-CXX_WARN_CFLAGS="$enchant_cxx_cv_warn_cflags"
-AC_SUBST(CXX_WARN_CFLAGS)
+AC_SUBST([ISYSTEM])
 
 ENCHANT_CFLAGS=$GLIB_CFLAGS
 ENCHANT_LIBS=$GLIB_LIBS
diff --git a/gl/build-aux/g++-warning.spec b/gl/build-aux/g++-warning.spec
new file mode 100644
index 0000000..ae3e866
--- /dev/null
+++ b/gl/build-aux/g++-warning.spec
@@ -0,0 +1,100 @@
+# options to filter out, and why
+--all-warnings				alias for -Wall
+--extra-warnings			alias for -Wextra
+-frequire-return-statement		go
+-Waggregate-return			obsolescent
+-Waliasing				fortran
+-Walign-commons				fortran
+-Wampersand				fortran
+-Warray-bounds				covered by -Warray-bounds=
+-Warray-bounds=				handled specially by gl_MANYWARN_ALL_GCC
+-Warray-temporaries			fortran
+-Wassign-intercept			objc/objc++
+-Wbad-function-cast			c
+-Wc++0x-compat				c++ compatibility
+-Wc++11-compat				c++ compatibility
+-Wc++14-compat				c++ compatibility
+-Wc90-c99-compat			c compatibility
+-Wc99-c11-compat			c compatibility
+-Wcast-qual				FIXME maybe? too much noise; encourages bad changes
+-Wcast-result				d
+-Wc-binding-type			fortran
+-Wc++-compat				FIXME maybe? borderline.  some will want this
+-Wcharacter-truncation			fortran
+-Wcompare-reals				fortran
+-Wconversion-extra			fortran
+-Wconversion				FIXME maybe? too much noise; encourages bad changes
+-Wdeclaration-after-statement		FIXME: do not want.  others may
+-Wdesignated-init			c
+-Wdiscarded-array-qualifiers		c
+-Wdiscarded-qualifiers			c
+-Werror-implicit-function-declaration	deprecated
+-Wfloat-conversion			FIXME maybe? borderline.  some will want this
+-Wfloat-equal				FIXME maybe? borderline.  some will want this
+-Wformat				covered by -Wformat=2
+-Wformat=				gcc --help=warnings artifact
+-Wframe-larger-than=<number>		FIXME: choose something sane?
+-Wfunction-elimination			fortran
+-Wimplicit				c
+-Wimplicit-function-declaration		c
+-Wimplicit-int				c
+-Wimplicit-interface			fortran
+-Wimplicit-procedure			fortran
+-Wincompatible-pointer-types		c
+-Wint-conversion			c
+-Winteger-division			fortran
+-Wintrinsic-shadow			fortran
+-Wintrinsics-std			fortran
+-Wjump-misses-init			c
+-Wlarger-than-				gcc --help=warnings artifact
+-Wlarger-than=<number>			FIXME: choose something sane?
+-Wline-truncation			fortran
+-Wlong-long				obsolescent
+-Wmissing-format-attribute		obsolescent
+-Wmissing-noreturn			obsolescent
+-Wmissing-parameter-type		c
+-Wmissing-prototypes			c
+-Wnested-externs			c
+-Wnormalized				covered by -Wnormalized=
+-Wnormalized=<none|id|nfc|nfkc>		handled specially by gl_MANYWARN_ALL_GCC
+-Wold-style-declaration			c
+-Wold-style-definition			c
+-Woverride-init				c
+-Wpadded				FIXME maybe?  warns about "stabil" member in /usr/include/bits/timex.h
+-Wpedantic				FIXME: too strict?
+-Wpointer-sign				c
+-Wpointer-to-int-cast			c
+-Wproperty-assign-default		objc++
+-Wprotocol				objc++
+-Wrealloc-lhs-all			fortran
+-Wrealloc-lhs				fortran
+-Wreal-q-constant			fortran
+-Wredundant-decls			FIXME maybe? many _gl_cxxalias_dummy FPs
+-Wselector				objc and objc++
+-Wshadow-ivar				objc
+-Wshift-overflow			covered by -Wshift-overflow=2
+-Wshift-overflow=			gcc --help=warnings artifact
+-Wsign-compare				FIXME maybe? borderline.  some will want this
+-Wsign-conversion			FIXME maybe? borderline.  some will want this
+-Wstack-usage=				FIXME: choose something sane?
+-Wstrict-aliasing=			FIXME: choose something sane?
+-Wstrict-overflow=			FIXME: choose something sane?
+-Wstrict-prototypes			c
+-Wstrict-selector-match			objc and objc++
+-Wsurprising				fortran
+-Wswitch-enum				FIXME maybe? borderline.  some will want this
+-Wsynth					deprecated
+-Wtabs					fortran
+-Wtarget-lifetime			fortran
+-Wtraditional-conversion		obsolescent
+-Wtraditional				obsolescent
+-Wundeclared-selector			objc and objc++
+-Wundef					FIXME maybe? too many false positives
+-Wunderflow				fortran
+-Wunreachable-code			obsolescent no-op
+-Wunsuffixed-float-constants		triggers warning in gnulib's timespec.h
+-Wunused-const-variable			covered by -Wunusec-const-variable=2
+-Wunused-const-variable=		gcc --help=warnings artifact
+-Wunused-dummy-argument			fortran
+-Wuse-without-only			fortran
+-Wzerotrip				fortran
diff --git a/gl/m4/manywarnings-cxx.m4 b/gl/m4/manywarnings-cxx.m4
new file mode 100644
index 0000000..12c81b9
--- /dev/null
+++ b/gl/m4/manywarnings-cxx.m4
@@ -0,0 +1,288 @@
+# manywarnings.m4 serial 8
+dnl Copyright (C) 2008-2017 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl From Simon Josefsson
+
+# gl_MANYWARN_COMPLEMENT(OUTVAR, LISTVAR, REMOVEVAR)
+# --------------------------------------------------
+# Copy LISTVAR to OUTVAR except for the entries in REMOVEVAR.
+# Elements separated by whitespace.  In set logic terms, the function
+# does OUTVAR = LISTVAR \ REMOVEVAR.
+AC_DEFUN([gl_MANYWARN_COMPLEMENT],
+[
+  gl_warn_set=
+  set x $2; shift
+  for gl_warn_item
+  do
+    case " $3 " in
+      *" $gl_warn_item "*)
+        ;;
+      *)
+        gl_warn_set="$gl_warn_set $gl_warn_item"
+        ;;
+    esac
+  done
+  $1=$gl_warn_set
+])
+
+# gl_MANYWARN_ALL_GXX(VARIABLE)
+# -----------------------------
+# Add all documented G++ warning parameters to variable VARIABLE.
+# Note that you need to test them using gl_WARN_ADD if you want to
+# make sure your gcc understands it.
+AC_DEFUN([gl_MANYWARN_ALL_GXX],
+[
+  dnl First, check for some issues that only occur when combining multiple
+  dnl gcc warning categories.
+  AC_REQUIRE([AC_PROG_CXX])
+  if test -n "$GXX"; then
+
+    dnl Check if -W -Werror -Wno-missing-field-initializers is supported
+    dnl with the current $CXX $CXXFLAGS $CPPFLAGS.
+    AC_MSG_CHECKING([whether -Wno-missing-field-initializers is supported])
+    AC_CACHE_VAL([gl_cv_cc_nomfi_supported], [
+      gl_save_CXXFLAGS="$CXXFLAGS"
+      CXXFLAGS="$CXXFLAGS -W -Werror -Wno-missing-field-initializers"
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[]], [[]])],
+        [gl_cv_cc_nomfi_supported=yes],
+        [gl_cv_cc_nomfi_supported=no])
+      CXXFLAGS="$gl_save_CXXFLAGS"])
+    AC_MSG_RESULT([$gl_cv_cc_nomfi_supported])
+
+    if test "$gl_cv_cc_nomfi_supported" = yes; then
+      dnl Now check whether -Wno-missing-field-initializers is needed
+      dnl for the { 0, } construct.
+      AC_MSG_CHECKING([whether -Wno-missing-field-initializers is needed])
+      AC_CACHE_VAL([gl_cv_cc_nomfi_needed], [
+        gl_save_CXXFLAGS="$CXXFLAGS"
+        CXXFLAGS="$CXXFLAGS -W -Werror"
+        AC_COMPILE_IFELSE(
+          [AC_LANG_PROGRAM(
+             [[int f (void)
+               {
+                 typedef struct { int a; int b; } s_t;
+                 s_t s1 = { 0, };
+                 return s1.b;
+               }
+             ]],
+             [[]])],
+          [gl_cv_cc_nomfi_needed=no],
+          [gl_cv_cc_nomfi_needed=yes])
+        CXXFLAGS="$gl_save_CXXFLAGS"
+      ])
+      AC_MSG_RESULT([$gl_cv_cc_nomfi_needed])
+    fi
+
+    dnl Next, check if -Werror -Wuninitialized is useful with the
+    dnl user's choice of $CXXFLAGS; some versions of gcc warn that it
+    dnl has no effect if -O is not also used
+    AC_MSG_CHECKING([whether -Wuninitialized is supported])
+    AC_CACHE_VAL([gl_cv_cc_uninitialized_supported], [
+      gl_save_CXXFLAGS="$CXXFLAGS"
+      CXXFLAGS="$CXXFLAGS -Werror -Wuninitialized"
+      AC_COMPILE_IFELSE(
+        [AC_LANG_PROGRAM([[]], [[]])],
+        [gl_cv_cc_uninitialized_supported=yes],
+        [gl_cv_cc_uninitialized_supported=no])
+      CXXFLAGS="$gl_save_CXXFLAGS"])
+    AC_MSG_RESULT([$gl_cv_cc_uninitialized_supported])
+
+  fi
+
+  # List all gcc warning categories.
+  # To compare this list to your installed GCC's, run this Bash command:
+  #
+  # comm -3 \
+  #  <(sed -n 's/^  *\(-[^ ]*\) .*/\1/p' manywarnings-cxx.m4 | sort) \
+  #  <(gcc --help=warnings | sed -n 's/^  \(-[^ ]*\) .*/\1/p' | sort |
+  #      grep -v -x -f <(
+  #         awk '/^[^#]/ {print $1}' ../build-aux/g++-warning.spec))
+
+  gl_manywarn_set=
+  for gl_manywarn_item in \
+    -W \
+    -Wabi \
+    -Wabi-tag \
+    -Waddress \
+    -Waggressive-loop-optimizations \
+    -Wall \
+    -Wattributes \
+    -Wbool-compare \
+    -Wbuiltin-macro-redefined \
+    -Wcast-align \
+    -Wchar-subscripts \
+    -Wchkp \
+    -Wclobbered \
+    -Wcomment \
+    -Wcomments \
+    -Wconditionally-supported \
+    -Wconversion-null \
+    -Wcoverage-mismatch \
+    -Wcpp \
+    -Wctor-dtor-privacy \
+    -Wdate-time \
+    -Wdelete-incomplete \
+    -Wdelete-non-virtual-dtor \
+    -Wdeprecated \
+    -Wdeprecated-declarations \
+    -Wdisabled-optimization \
+    -Wdiv-by-zero \
+    -Wdouble-promotion \
+    -Weffc++ \
+    -Wempty-body \
+    -Wendif-labels \
+    -Wenum-compare \
+    -Wextra \
+    -Wformat-contains-nul \
+    -Wformat-extra-args \
+    -Wformat-nonliteral \
+    -Wformat-security \
+    -Wformat-signedness \
+    -Wformat-y2k \
+    -Wformat-zero-length \
+    -Wfree-nonheap-object \
+    -Wignored-qualifiers \
+    -Winherited-variadic-ctor \
+    -Winit-self \
+    -Winline \
+    -Wint-to-pointer-cast \
+    -Winvalid-memory-model \
+    -Winvalid-offsetof \
+    -Winvalid-pch \
+    -Wliteral-suffix \
+    -Wlogical-not-parentheses \
+    -Wlogical-op \
+    -Wmain \
+    -Wmaybe-uninitialized \
+    -Wmemset-transposed-args \
+    -Wmissing-braces \
+    -Wmissing-declarations \
+    -Wmissing-field-initializers \
+    -Wmissing-include-dirs \
+    -Wmultichar \
+    -Wnarrowing \
+    -Wnoexcept \
+    -Wnon-template-friend \
+    -Wnon-virtual-dtor \
+    -Wnonnull \
+    -Wodr \
+    -Wold-style-cast \
+    -Wopenmp-simd \
+    -Woverflow \
+    -Woverlength-strings \
+    -Woverloaded-virtual \
+    -Wpacked \
+    -Wpacked-bitfield-compat \
+    -Wparentheses \
+    -Wpmf-conversions \
+    -Wpointer-arith \
+    -Wpragmas \
+    -Wreorder \
+    -Wreturn-local-addr \
+    -Wreturn-type \
+    -Wsequence-point \
+    -Wshadow \
+    -Wshift-count-negative \
+    -Wshift-count-overflow \
+    -Wsign-promo \
+    -Wsized-deallocation \
+    -Wsizeof-array-argument \
+    -Wsizeof-pointer-memaccess \
+    -Wstack-protector \
+    -Wstrict-aliasing \
+    -Wstrict-null-sentinel \
+    -Wstrict-overflow \
+    -Wsuggest-attribute=const \
+    -Wsuggest-attribute=format \
+    -Wsuggest-attribute=noreturn \
+    -Wsuggest-attribute=pure \
+    -Wsuggest-final-methods \
+    -Wsuggest-final-types \
+    -Wsuggest-override \
+    -Wswitch \
+    -Wswitch-bool \
+    -Wswitch-default \
+    -Wsync-nand \
+    -Wsystem-headers \
+    -Wtrampolines \
+    -Wtrigraphs \
+    -Wtype-limits \
+    -Wuninitialized \
+    -Wunknown-pragmas \
+    -Wunsafe-loop-optimizations \
+    -Wunused \
+    -Wunused-but-set-parameter \
+    -Wunused-but-set-variable \
+    -Wunused-function \
+    -Wunused-label \
+    -Wunused-local-typedefs \
+    -Wunused-macros \
+    -Wunused-parameter \
+    -Wunused-result \
+    -Wunused-value \
+    -Wunused-variable \
+    -Wuseless-cast \
+    -Wvarargs \
+    -Wvariadic-macros \
+    -Wvector-operation-performance \
+    -Wvirtual-move-assign \
+    -Wvla \
+    -Wvolatile-register-var \
+    -Wwrite-strings \
+    -Wzero-as-null-pointer-constant \
+    \
+    ; do
+    gl_manywarn_set="$gl_manywarn_set $gl_manywarn_item"
+  done
+
+  # gcc --help=warnings outputs an unusual form for these options; list
+  # them here so that the above 'comm' command doesn't report a false match.
+  gl_manywarn_set="$gl_manywarn_set -Warray-bounds=2"
+  gl_manywarn_set="$gl_manywarn_set -Wnormalized=nfc"
+  gl_manywarn_set="$gl_manywarn_set -Wshift-overflow=2"
+  gl_manywarn_set="$gl_manywarn_set -Wunused-const-variable=2"
+
+  # These are needed for older GCC versions.
+  if test -n "$GXX"; then
+    case `($CXX --version) 2>/dev/null` in
+      'g++ (GCC) '[[0-3]].* | \
+      'g++ (GCC) '4.[[0-7]].*)
+        gl_manywarn_set="$gl_manywarn_set -fdiagnostics-show-option"
+        gl_manywarn_set="$gl_manywarn_set -funit-at-a-time"
+          ;;
+    esac
+  fi
+
+  # Disable specific options as needed.
+  if test "$gl_cv_cc_nomfi_needed" = yes; then
+    gl_manywarn_set="$gl_manywarn_set -Wno-missing-field-initializers"
+  fi
+
+  if test "$gl_cv_cc_uninitialized_supported" = no; then
+    gl_manywarn_set="$gl_manywarn_set -Wno-uninitialized"
+  fi
+
+  $1=$gl_manywarn_set
+])
+
+# gl_CXX_WARN_ADD(OPTION, [VARIABLE = WARN_CFLAGS],
+#             [PROGRAM = AC_LANG_PROGRAM()])
+# ---------------------------------------------
+# Adds parameter to WARN_CXXFLAGS if the compiler supports it when
+# compiling PROGRAM.  For example, gl_CXX_WARN_ADD([-Wparentheses]).
+#
+# If VARIABLE is a variable name, AC_SUBST it.
+AC_DEFUN([gl_CXX_WARN_ADD],
+[AC_REQUIRE([gl_UNKNOWN_WARNINGS_ARE_ERRORS])
+gl_COMPILER_OPTION_IF([$1],
+  [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CXXFLAGS]], [[$2]]), [" $1"])],
+  [],
+  [$3])
+m4_ifval([$2],
+         [AS_LITERAL_IF([$2], [AC_SUBST([$2])])],
+         [AC_SUBST([WARN_CXXFLAGS])])dnl
+])
diff --git a/gl/modules/manywarnings-cxx b/gl/modules/manywarnings-cxx
new file mode 100644
index 0000000..cf7acf5
--- /dev/null
+++ b/gl/modules/manywarnings-cxx
@@ -0,0 +1,16 @@
+Description:
+Helper M4 functions to help work out a set of warning parameters to use.
+
+Files:
+m4/manywarnings-cxx.m4
+
+Depends-on:
+warnings
+
+configure.ac:
+
+License:
+unlimited
+
+Maintainer:
+Simon Josefsson
diff --git a/m4/.gitignore b/m4/.gitignore
index 90a122e..b81f2a1 100644
--- a/m4/.gitignore
+++ b/m4/.gitignore
@@ -35,3 +35,6 @@
 /wchar_t.m4
 /wint_t.m4
 /ssize_t.m4
+/manywarnings.m4
+/warnings.m4
+/manywarnings-cxx.m4
diff --git a/m4/gnulib-cache.m4 b/m4/gnulib-cache.m4
index 0b32dda..89efb36 100644
--- a/m4/gnulib-cache.m4
+++ b/m4/gnulib-cache.m4
@@ -27,13 +27,16 @@
 
 
 # Specification in the form of a command-line invocation:
-#   gnulib-tool --import --local-dir=gl --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --no-conditional-dependencies --libtool --macro-prefix=gl bootstrap flock
+#   gnulib-tool --import --local-dir=gl --lib=libgnu --source-base=lib --m4-base=m4 --doc-base=doc --tests-base=tests --aux-dir=build-aux --no-conditional-dependencies --libtool --macro-prefix=gl bootstrap flock manywarnings manywarnings-cxx snippet/unused-parameter
 
 # Specification in the form of a few gnulib-tool.m4 macro invocations:
 gl_LOCAL_DIR([gl])
 gl_MODULES([
   bootstrap
   flock
+  manywarnings
+  manywarnings-cxx
+  snippet/unused-parameter
 ])
 gl_AVOID([])
 gl_SOURCE_BASE([lib])
diff --git a/src/Makefile.am b/src/Makefile.am
index fb8f0c5..0d2f32b 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,6 +1,6 @@
 SUBDIRS=. aspell ispell uspell myspell hspell applespell voikko zemberek
 
-AM_CPPFLAGS=-I$(top_srcdir) $(ENCHANT_CFLAGS) $(CC_WARN_CFLAGS)
+AM_CPPFLAGS = -I$(top_srcdir) $(ISYSTEM)$(top_builddir)/lib $(ISYSTEM)$(top_srcdir)/lib $(ENCHANT_CFLAGS) $(WARN_CFLAGS)
 
 lib_LTLIBRARIES = libenchant.la
 
diff --git a/src/aspell/Makefile.am b/src/aspell/Makefile.am
index 18bfcf1..5e54d1d 100644
--- a/src/aspell/Makefile.am
+++ b/src/aspell/Makefile.am
@@ -4,7 +4,7 @@ else
 target_lib =
 endif
 
-AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(CC_WARN_CFLAGS) @ASPELL_INC@ -D_ENCHANT_BUILD=1 @ASPELL_CFLAGS@
+AM_CPPFLAGS = -I$(top_srcdir) $(ISYSTEM)$(top_builddir)/lib $(ISYSTEM)$(top_srcdir)/lib -I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(WARN_CFLAGS) @ASPELL_INC@ -D_ENCHANT_BUILD=1 @ASPELL_CFLAGS@
 
 aspell_LTLIBRARIES = $(target_lib)
 aspelldir= $(libdir)/enchant
diff --git a/src/aspell/aspell_provider.c b/src/aspell/aspell_provider.c
index 9a448b9..03bd1b9 100644
--- a/src/aspell/aspell_provider.c
+++ b/src/aspell/aspell_provider.c
@@ -28,6 +28,8 @@
  * do so, delete this exception statement from your version.
  */
 
+#include "config.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -37,6 +39,7 @@
 
 #include "enchant.h"
 #include "enchant-provider.h"
+#include "unused-parameter.h"
 
 ENCHANT_PLUGIN_DECLARE("Aspell")
 
@@ -150,7 +153,7 @@ aspell_dict_store_replacement (EnchantDict * me,
 }
 
 static EnchantDict *
-aspell_provider_request_dict (EnchantProvider * me, const char *const tag)
+aspell_provider_request_dict (EnchantProvider * me _GL_UNUSED_PARAMETER, const char *const tag)
 {
 	EnchantDict *dict;
 	AspellSpeller *manager;
@@ -183,7 +186,7 @@ aspell_provider_request_dict (EnchantProvider * me, const char *const tag)
 }
 
 static void
-aspell_provider_dispose_dict (EnchantProvider * me, EnchantDict * dict)
+aspell_provider_dispose_dict (EnchantProvider * me _GL_UNUSED_PARAMETER, EnchantDict * dict)
 {
 	AspellSpeller *manager;
 	
@@ -194,7 +197,7 @@ aspell_provider_dispose_dict (EnchantProvider * me, EnchantDict * dict)
 }
 
 static char ** 
-aspell_provider_list_dicts (EnchantProvider * me, 
+aspell_provider_list_dicts (EnchantProvider * me _GL_UNUSED_PARAMETER, 
 			    size_t * out_n_dicts)
 {
 	AspellConfig * spell_config;
@@ -235,7 +238,7 @@ aspell_provider_list_dicts (EnchantProvider * me,
 }
 
 static void
-aspell_provider_free_string_list (EnchantProvider * me, char **str_list)
+aspell_provider_free_string_list (EnchantProvider * me _GL_UNUSED_PARAMETER, char **str_list)
 {
 	g_strfreev (str_list);
 }
@@ -247,13 +250,13 @@ aspell_provider_dispose (EnchantProvider * me)
 }
 
 static const char *
-aspell_provider_identify (EnchantProvider * me)
+aspell_provider_identify (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "aspell";
 }
 
 static const char *
-aspell_provider_describe (EnchantProvider * me)
+aspell_provider_describe (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "Aspell Provider";
 }
diff --git a/src/enchant-lsmod.c b/src/enchant-lsmod.c
index 6ed3f4f..05d56bc 100644
--- a/src/enchant-lsmod.c
+++ b/src/enchant-lsmod.c
@@ -34,6 +34,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include "unused-parameter.h"
 
 #include "enchant.h"
 #include "enchant-provider.h"
@@ -41,8 +42,8 @@
 static void
 describe_dict (const char * const lang_tag,
 	       const char * const provider_name,
-	       const char * const provider_desc,
-	       const char * const provider_file,
+	       const char * const provider_desc _GL_UNUSED_PARAMETER,
+	       const char * const provider_file _GL_UNUSED_PARAMETER,
 	       void * user_data)
 {
 	FILE * out = (FILE *)user_data;
@@ -52,7 +53,7 @@ describe_dict (const char * const lang_tag,
 static void
 enumerate_providers (const char * name,
 		     const char * desc,
-		     const char * file,
+		     const char * file _GL_UNUSED_PARAMETER,
 		     void * user_data)
 {
 	FILE * out = (FILE *)user_data;
@@ -62,8 +63,8 @@ enumerate_providers (const char * name,
 static void
 enumerate_dicts (const char * const lang_tag,
 		 const char * const provider_name,
-		 const char * const provider_desc,
-		 const char * const provider_file,
+		 const char * const provider_desc _GL_UNUSED_PARAMETER,
+		 const char * const provider_file _GL_UNUSED_PARAMETER,
 		 void * user_data)
 {
 	FILE * out = (FILE *)user_data;
diff --git a/src/enchant.c b/src/enchant.c
index 9c59ba2..98756bc 100644
--- a/src/enchant.c
+++ b/src/enchant.c
@@ -28,6 +28,8 @@
  * do so, delete this exception statement from your version.
  */
 
+#include "config.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -41,6 +43,7 @@
 #include "enchant.h"
 #include "enchant-provider.h"
 #include "pwl.h"
+#include "unused-parameter.h"
 
 #if defined(__APPLE__) && defined(__MACH__)
 #define ENCHANT_USER_PATH_EXTENSION "Library", "Application Support", "Enchant"
@@ -314,7 +317,7 @@ enchant_ascii_strdown (gchar *str,
 /* returns TRUE if tag is valid
  * for requires alphanumeric ASCII or underscore
  */
-static int
+static _GL_ATTRIBUTE_PURE int
 enchant_is_valid_dictionary_tag(const char * const tag)
 {
 	const char * it;
@@ -670,11 +673,7 @@ enchant_dict_check (EnchantDict * dict, const char *const word, ssize_t len)
  * returns the number of items in @suggs after merge is complete
  */
 static int
-enchant_dict_merge_suggestions(EnchantDict * dict, 
-								char ** suggs,
-								size_t n_suggs,
-								char ** new_suggs,
-								size_t n_new_suggs)
+enchant_dict_merge_suggestions(char ** suggs, size_t n_suggs, char ** new_suggs, size_t n_new_suggs)
 {
 	size_t i, j;
 
@@ -809,13 +808,11 @@ enchant_dict_suggest (EnchantDict * dict, const char *const word,
 			suggs = g_new0 (char *, n_suggs + 1);
 
 			/* Copy over suggestions from dict, if no dupes */
-			n_suggs = enchant_dict_merge_suggestions(dict, 
-								 suggs, 0, 
+			n_suggs = enchant_dict_merge_suggestions(suggs, 0, 
 								 dict_suggs, n_dict_suggs);
 
 			/* Copy over suggestions from pwl, if no dupes */
-			n_suggs = enchant_dict_merge_suggestions(dict, 
-								 suggs, n_suggs, 
+			n_suggs = enchant_dict_merge_suggestions(suggs, n_suggs, 
 								 pwl_suggs, n_pwl_suggs);
 			if(n_suggs == 0)
 			{
@@ -1179,7 +1176,7 @@ enchant_load_providers_in_dir (EnchantBroker * broker, const char *dir_name)
 {
 	GModule *module = NULL;
 	GDir *dir;
-	G_CONST_RETURN char *dir_entry;
+	const char *dir_entry;
 	size_t entry_len, g_module_suffix_len;
 	
 	char * filename;
@@ -1423,7 +1420,7 @@ enchant_dict_destroyed (gpointer data)
 }
 
 static void
-enchant_provider_free (gpointer data, gpointer user_data)
+enchant_provider_free (gpointer data, gpointer user_data _GL_UNUSED_PARAMETER)
 {
 	EnchantProvider *provider;
 	GModule *module;
@@ -2088,7 +2085,7 @@ enchant_get_dirs_from_param (EnchantBroker * broker, const char * const param_na
 	return _enchant_get_dirs_from_string (param_value);
 }
 
-ENCHANT_MODULE_EXPORT(const char *)
+ENCHANT_MODULE_EXPORT(const char *) _GL_ATTRIBUTE_CONST
 enchant_get_version (void) {
 	return ENCHANT_VERSION_STRING;
 }
diff --git a/src/hspell/Makefile.am b/src/hspell/Makefile.am
index 28560c3..1d11782 100644
--- a/src/hspell/Makefile.am
+++ b/src/hspell/Makefile.am
@@ -4,7 +4,7 @@ else
 target_lib =
 endif
 
-AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(CC_WARN_CFLAGS) $(HSPELL_CFLAGS) -D_ENCHANT_BUILD=1
+AM_CPPFLAGS = -I$(top_srcdir) $(ISYSTEM)$(top_builddir)/lib $(ISYSTEM)$(top_srcdir)/lib -I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(WARN_CFLAGS) $(HSPELL_CFLAGS) -D_ENCHANT_BUILD=1
 
 hspell_LTLIBRARIES = $(target_lib)
 hspelldir= $(libdir)/enchant
diff --git a/src/hspell/hspell_provider.c b/src/hspell/hspell_provider.c
index 99e7287..bd52aff 100644
--- a/src/hspell/hspell_provider.c
+++ b/src/hspell/hspell_provider.c
@@ -29,6 +29,8 @@
  * do so, delete this exception statement from your version.
  */
 
+#include "config.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -38,6 +40,7 @@
 
 #include "enchant.h"
 #include "enchant-provider.h"
+#include "unused-parameter.h"
 
 ENCHANT_PLUGIN_DECLARE ("Hspell")
 
@@ -205,7 +208,7 @@ hspell_provider_request_dict (EnchantProvider * me, const char *const tag)
 }
 
 static void
-hspell_provider_dispose_dict (EnchantProvider * me, EnchantDict * dict)
+hspell_provider_dispose_dict (EnchantProvider * me _GL_UNUSED_PARAMETER, EnchantDict * dict)
 {
 	struct dict_radix *hspell_dict;
 	
@@ -217,7 +220,7 @@ hspell_provider_dispose_dict (EnchantProvider * me, EnchantDict * dict)
 /* test for the existence of, then return $prefix/share/hspell/hebrew.wgz */
 
 static char ** 
-hspell_provider_list_dicts (EnchantProvider * me, 
+hspell_provider_list_dicts (EnchantProvider * me _GL_UNUSED_PARAMETER, 
 			    size_t * out_n_dicts)
 {
 	const char * dictionary_path;
@@ -246,7 +249,7 @@ hspell_provider_dictionary_exists (struct str_enchant_provider * me,
 }
 
 static void
-hspell_provider_free_string_list (EnchantProvider * me, char **str_list)
+hspell_provider_free_string_list (EnchantProvider * me  _GL_UNUSED_PARAMETER, char **str_list)
 {
 	g_strfreev (str_list);
 }
@@ -258,13 +261,13 @@ hspell_provider_dispose (EnchantProvider * me)
 }
 
 static const char *
-hspell_provider_identify (EnchantProvider * me)
+hspell_provider_identify (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "hspell";
 }
 
 static const char *
-hspell_provider_describe (EnchantProvider * me)
+hspell_provider_describe (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "Hspell Provider";
 }
diff --git a/src/ispell/Makefile.am b/src/ispell/Makefile.am
index da20b6d..b62649c 100644
--- a/src/ispell/Makefile.am
+++ b/src/ispell/Makefile.am
@@ -4,7 +4,7 @@ else
 target_lib =
 endif
 
-AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(CXX_WARN_CFLAGS) $(ISPELL_CFLAGS) -D_ENCHANT_BUILD=1
+AM_CPPFLAGS = -I$(top_srcdir) $(ISYSTEM)$(top_builddir)/lib $(ISYSTEM)$(top_srcdir)/lib -I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(WARN_CXXFLAGS) $(ISPELL_CFLAGS) -D_ENCHANT_BUILD=1
 
 ispell_LTLIBRARIES = $(target_lib)
 ispelldir= $(libdir)/enchant
diff --git a/src/ispell/ispell_checker.cpp b/src/ispell/ispell_checker.cpp
index fcc9dd4..41b9eb2 100644
--- a/src/ispell/ispell_checker.cpp
+++ b/src/ispell/ispell_checker.cpp
@@ -1,4 +1,6 @@
 /* vim: set sw=8: -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
+#include "config.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h> 
@@ -10,6 +12,7 @@
 #include "sp_spell.h"
 #include "ispell_checker.h"
 #include "enchant.h"
+#include "unused-parameter.h"
 
 #ifndef ENCHANT_ISPELL_HOME_DIR
 #define ENCHANT_ISPELL_HOME_DIR "ispell"
@@ -67,6 +70,12 @@ static const IspellMap ispell_map [] = {
 
 static const size_t size_ispell_map = G_N_ELEMENTS(ispell_map);
 
+static void
+ispell_checker_free_helper (gpointer p, gpointer user _GL_UNUSED_PARAMETER)
+{
+	g_free (p);
+}
+
 static bool
 g_iconv_is_valid(GIConv i)
 {
@@ -99,16 +108,39 @@ ISpellChecker::ISpellChecker(EnchantBroker * broker)
      m_nd(NULL),
      m_so(NULL),
      m_se(NULL),
+     m_sg(0),
      m_ti(NULL),
      m_te(NULL),
+     m_li(0),
+     m_co(0),
+     m_numhits(0),
      m_hashstrings(NULL),
+     m_hashheader({}),
      m_hashtbl(NULL),
+     m_hashsize(0),
+     m_aflag(0),
+     m_cflag(0),
+     m_lflag(0),
+     m_incfileflag(0),
+     m_nodictflag(0),
+     m_uerasechar(0),
+     m_ukillchar(0),
+     m_laststringch(0U),
+     m_defdupchar(0),
+     m_numpflags(0),
+     m_numsflags(0),
      m_pflaglist(NULL),
      m_sflaglist(NULL),
      m_chartypes(NULL),
      m_infile(NULL),
      m_outfile(NULL),
      m_askfilename(NULL),
+     m_changes(0),
+     m_readonly(0),
+     m_quit(0),
+     m_pcount(0),
+     m_maxposslen(0),
+     m_easypossibilities(0),
      m_Trynum(0),
      m_translate_in(G_ICONV_INVALID),
      m_translate_out(G_ICONV_INVALID)
@@ -168,7 +200,7 @@ ISpellChecker::checkWord(const char * const utf8Word, size_t length)
 			len_out = sizeof( szWord ) - 1;
 			result = g_iconv(m_translate_in, &In, &len_in, &Out, &len_out);
 			g_free(normalizedWord);
-			if ((size_t)-1 == result)
+			if (static_cast<size_t>(-1) == result)
 				return false;
 			*Out = '\0';
 		}
@@ -215,7 +247,7 @@ ISpellChecker::suggestWord(const char * const utf8Word, size_t length,
 			len_out = sizeof( word8 ) - 1;
 			result = g_iconv(m_translate_in, &In, &len_in, &Out, &len_out);
 			g_free(normalizedWord);
-			if ((size_t)-1 == result)
+			if (static_cast<size_t>(-1) == result)
 				return NULL;
 			*Out = '\0';
 		}
@@ -250,11 +282,11 @@ ISpellChecker::suggestWord(const char * const utf8Word, size_t length,
 						
 						size_t len_in, len_out;
 						char *In = m_possibilities[c];
-						char *Out = reinterpret_cast<char *>(utf8Sugg);
+						char *Out = utf8Sugg;
 						
 						len_in = l;
 						len_out = INPUTWORDLEN + MAXAFFIXLEN;
-						if ((size_t)-1 == g_iconv(m_translate_out, &In, &len_in, &Out, &len_out)) {
+						if (static_cast<size_t>(-1) == g_iconv(m_translate_out, &In, &len_in, &Out, &len_out)) {
 							*out_n_suggestions = c;
 							return sugg_arr;
 						}
@@ -280,11 +312,11 @@ ispell_checker_get_dictionary_dirs (EnchantBroker * broker)
 		
 		for (iter = config_dirs; iter; iter = iter->next)
 			{
-				dirs = g_slist_append (dirs, g_build_filename ((const gchar *)iter->data, 
-									       ENCHANT_ISPELL_HOME_DIR, NULL));
+				dirs = g_slist_append (dirs, g_build_filename (static_cast<const gchar *>(iter->data), 
+									       ENCHANT_ISPELL_HOME_DIR, nullptr));
 			}
 
-		g_slist_foreach (config_dirs, (GFunc)g_free, NULL);
+		g_slist_foreach (config_dirs, ispell_checker_free_helper, nullptr);
 		g_slist_free (config_dirs);
 	}
 
@@ -292,7 +324,7 @@ ispell_checker_get_dictionary_dirs (EnchantBroker * broker)
 	char * enchant_prefix = enchant_get_prefix_dir();
 	if(enchant_prefix)
 		{
-			char * ispell_prefix = g_build_filename(enchant_prefix, "share", "enchant", "ispell", NULL);
+			char * ispell_prefix = g_build_filename(enchant_prefix, "share", "enchant", "ispell", nullptr);
 			g_free(enchant_prefix);
 			dirs = g_slist_append (dirs, ispell_prefix);
 		}
@@ -308,10 +340,10 @@ ispell_checker_get_dictionary_dirs (EnchantBroker * broker)
 		
 		for (iter = config_dirs; iter; iter = iter->next)
 			{
-				dirs = g_slist_append (dirs, g_strdup ((const gchar *)iter->data));
+				dirs = g_slist_append (dirs, g_strdup (static_cast<const gchar *>(iter->data)));
 			}
 
-		g_slist_foreach (config_dirs, (GFunc)g_free, NULL);
+		g_slist_foreach (config_dirs, ispell_checker_free_helper, nullptr);
 		g_slist_free (config_dirs);
 	}
 
@@ -330,12 +362,12 @@ s_buildHashNames (std::vector<std::string> & names, EnchantBroker * broker, cons
 		{
 			char *tmp;
 
-			tmp = g_build_filename ((const gchar *)iter->data, dict, NULL);
+			tmp = g_build_filename (static_cast<const gchar *>(iter->data), dict, nullptr);
 			names.push_back (tmp);
 			g_free (tmp);
 		}
 
-	g_slist_foreach (dirs, (GFunc)g_free, NULL);
+	g_slist_foreach (dirs, ispell_checker_free_helper, nullptr);
 	g_slist_free (dirs);
 }
 
@@ -371,7 +403,7 @@ ISpellChecker::loadDictionaryForLanguage ( const char * szLang )
 	
 	for (size_t i = 0; i < size_ispell_map; i++)
 		{
-			const IspellMap * mapping = (const IspellMap *)(&(ispell_map[i]));
+			const IspellMap * mapping = &(ispell_map[i]);
 			if (!strcmp (szLang, mapping->lang))
 				{
 					szFile = mapping->dict;
@@ -389,14 +421,14 @@ ISpellChecker::loadDictionaryForLanguage ( const char * szLang )
 		return false;
 	
 	// one of the two above calls succeeded
-	setDictionaryEncoding (hashname, encoding);
+	setDictionaryEncoding (encoding);
 	g_free (hashname);
 
 	return true;
 }
 
 void
-ISpellChecker::setDictionaryEncoding( const char * hashname, const char * encoding )
+ISpellChecker::setDictionaryEncoding( const char * encoding )
 {
 	/* Get Hash encoding from XML file. This should always work! */
 	try_autodetect_charset(encoding);
@@ -405,7 +437,7 @@ ISpellChecker::setDictionaryEncoding( const char * hashname, const char * encodi
 		{
 			/* We still have to setup prefstringchar*/
 			prefstringchar = findfiletype("utf8", 1, deftflag < 0 ? &deftflag
-						      : static_cast<int *>(NULL));
+						      : nullptr);
 			
 			if (prefstringchar < 0)
 				{
@@ -414,7 +446,7 @@ ISpellChecker::setDictionaryEncoding( const char * hashname, const char * encodi
 						{
 							sprintf(teststring, "latin%d", n1);
 							prefstringchar = findfiletype(teststring, 1,				      
-										      deftflag < 0 ? &deftflag : static_cast<int *>(NULL));
+										      deftflag < 0 ? &deftflag : nullptr);
 							if (prefstringchar >= 0) 
 								break;
 						}
@@ -424,7 +456,7 @@ ISpellChecker::setDictionaryEncoding( const char * hashname, const char * encodi
 		}
 	
 	/* Test for UTF-8 first */
-	prefstringchar = findfiletype("utf8", 1, deftflag < 0 ? &deftflag : static_cast<int *>(NULL));
+	prefstringchar = findfiletype("utf8", 1, deftflag < 0 ? &deftflag : nullptr);
 	if (prefstringchar >= 0)
 		{
 			m_translate_in = g_iconv_open("UTF-8", "UTF-8");
@@ -438,11 +470,11 @@ ISpellChecker::setDictionaryEncoding( const char * hashname, const char * encodi
 	if (!g_iconv_is_valid(m_translate_in))
 		{
 			/* Look for "altstringtype" names from latin1 to latin15 */
-			for(int n1 = 1; n1 <= 15; n1++)
+			for(unsigned n1 = 1; n1 <= 15; n1++)
 				{
 					char * teststring = g_strdup_printf("latin%u", n1);
 					prefstringchar = findfiletype(teststring, 1,
-								      deftflag < 0 ? &deftflag : static_cast<int *>(NULL));
+								      deftflag < 0 ? &deftflag : nullptr);
 					if (prefstringchar >= 0)
 						{
 							m_translate_in = g_iconv_open(teststring, "UTF-8");
@@ -474,7 +506,7 @@ ISpellChecker::requestDictionary(const char *szLang)
 			std::string shortened_dict (szLang);
 			size_t uscore_pos;
 			
-			if ((uscore_pos = shortened_dict.rfind ('_')) != ((size_t)-1)) {
+			if ((uscore_pos = shortened_dict.rfind ('_')) != (static_cast<size_t>(-1))) {
 				shortened_dict = shortened_dict.substr(0, uscore_pos);
 				if (!loadDictionaryForLanguage (shortened_dict.c_str()))
 					return false;
@@ -498,7 +530,7 @@ ispell_dict_suggest (EnchantDict * me, const char *const word,
 {
 	ISpellChecker * checker;
 	
-	checker = (ISpellChecker *) me->user_data;
+	checker = static_cast<ISpellChecker *>(me->user_data);
 	return checker->suggestWord (word, len, out_n_suggs);
 }
 
@@ -507,7 +539,7 @@ ispell_dict_check (EnchantDict * me, const char *const word, size_t len)
 {
 	ISpellChecker * checker;
 	
-	checker = (ISpellChecker *) me->user_data;
+	checker = static_cast<ISpellChecker *>(me->user_data);
 	
 	if (checker->checkWord(word, len))
 		return 0;
@@ -534,7 +566,7 @@ ispell_provider_request_dict (EnchantProvider * me, const char *const tag)
 	}
 	
 	dict = g_new0 (EnchantDict, 1);
-	dict->user_data = (void *) checker;
+	dict->user_data = checker;
 	dict->check = ispell_dict_check;
 	dict->suggest = ispell_dict_suggest;
 	// don't implement session or personal
@@ -543,11 +575,11 @@ ispell_provider_request_dict (EnchantProvider * me, const char *const tag)
 }
 
 static void
-ispell_provider_dispose_dict (EnchantProvider * me, EnchantDict * dict)
+ispell_provider_dispose_dict (EnchantProvider * me _GL_UNUSED_PARAMETER, EnchantDict * dict)
 {
 	ISpellChecker * checker;
 	
-	checker = (ISpellChecker *) dict->user_data;
+	checker = static_cast<ISpellChecker *>(dict->user_data);
 	delete checker;
 	
 	g_free (dict);
@@ -589,7 +621,7 @@ ispell_provider_list_dictionaries (EnchantProvider * me,
 	*out_n_dicts = nb;
 	if (nb == 0) {
 		g_free (out_dicts);
-		out_dicts = NULL;
+		out_dicts = nullptr;
 	}
 
 	return out_dicts;
@@ -606,7 +638,7 @@ ispell_provider_dictionary_exists (struct str_enchant_provider * me,
 	
 	for (size_t i = 0; i < size_ispell_map; i++)
 		{
-			const IspellMap * mapping = (const IspellMap *)(&(ispell_map[i]));
+			const IspellMap * mapping = &(ispell_map[i]);
 			if (!strcmp (tag, mapping->lang) || !strcmp (shortened_dict.c_str(), mapping->lang)) 
 				return _ispell_provider_dictionary_exists(me->owner, mapping->dict);
 		}
@@ -615,7 +647,7 @@ ispell_provider_dictionary_exists (struct str_enchant_provider * me,
 }
 
 static void
-ispell_provider_free_string_list (EnchantProvider * me, char **str_list)
+ispell_provider_free_string_list (EnchantProvider * me _GL_UNUSED_PARAMETER, char **str_list)
 {
 	g_strfreev (str_list);
 }
@@ -627,13 +659,13 @@ ispell_provider_dispose (EnchantProvider * me)
 }
 
 static const char *
-ispell_provider_identify (EnchantProvider * me)
+ispell_provider_identify (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "ispell";
 }
 
 static const char *
-ispell_provider_describe (EnchantProvider * me)
+ispell_provider_describe (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "Ispell Provider";
 }
diff --git a/src/ispell/ispell_checker.h b/src/ispell/ispell_checker.h
index 8ffcc31..af4acda 100644
--- a/src/ispell/ispell_checker.h
+++ b/src/ispell/ispell_checker.h
@@ -26,7 +26,7 @@ private:
 
 	char * loadDictionary (const char * szLang );
 	bool   loadDictionaryForLanguage ( const char * szLang );
-	void   setDictionaryEncoding ( const char * hashname, const char * enc );
+	void   setDictionaryEncoding ( const char * enc );
 
 	//
 	// The member functions after this point were formerly global functions
diff --git a/src/myspell/Makefile.am b/src/myspell/Makefile.am
index f278a37..cfea67b 100644
--- a/src/myspell/Makefile.am
+++ b/src/myspell/Makefile.am
@@ -4,7 +4,7 @@ else
 target_lib =
 endif
 
-AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(MYSPELL_CFLAGS) $(CXX_WARN_CFLAGS) -D_ENCHANT_BUILD=1
+AM_CPPFLAGS = -I$(top_srcdir) $(ISYSTEM)$(top_builddir)/lib $(ISYSTEM)$(top_srcdir)/lib -I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(MYSPELL_CFLAGS) $(WARN_CXXFLAGS) -D_ENCHANT_BUILD=1
 
 myspell_LTLIBRARIES = $(target_lib)
 myspelldir= $(libdir)/enchant
diff --git a/src/myspell/myspell_checker.cpp b/src/myspell/myspell_checker.cpp
index d04a726..8f4f128 100644
--- a/src/myspell/myspell_checker.cpp
+++ b/src/myspell/myspell_checker.cpp
@@ -28,6 +28,8 @@
  * do so, delete this exception statement from your version.
  */
 
+#include "config.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h> 
@@ -37,6 +39,7 @@
 
 #include "enchant.h"
 #include "enchant-provider.h"
+#include "unused-parameter.h"
 
 #include <hunspell/hunspell.hxx>
 
@@ -72,6 +75,12 @@ private:
 	EnchantBroker *m_broker;
 };
 
+static void
+myspell_checker_free_helper (gpointer p, gpointer user _GL_UNUSED_PARAMETER)
+{
+	g_free (p);
+}
+
 /***************************************************************************/
 
 static bool
@@ -109,7 +118,7 @@ MySpellChecker::checkWord(const char *utf8Word, size_t len)
 	size_t len_out = sizeof( word8 ) - 1;
 	size_t result = g_iconv(m_translate_in, &in, &len_in, &out, &len_out);
 	g_free(normalizedWord);
-	if ((size_t)-1 == result)
+	if (static_cast<size_t>(-1) == result)
 		return false;
 	*out = '\0';
 	if (myspell->spell(word8))
@@ -124,7 +133,7 @@ MySpellChecker::suggestWord(const char* const utf8Word, size_t len, size_t *nsug
 	if (len > MAXWORDLEN 
 		|| !g_iconv_is_valid(m_translate_in)
 		|| !g_iconv_is_valid(m_translate_out))
-		return 0;
+		return nullptr;
 
 	// the 8bit encodings use precomposed forms
 	char *normalizedWord = g_utf8_normalize (utf8Word, len, G_NORMALIZE_NFC);
@@ -135,8 +144,8 @@ MySpellChecker::suggestWord(const char* const utf8Word, size_t len, size_t *nsug
 	size_t len_out = sizeof(word8) - 1;
 	size_t result = g_iconv(m_translate_in, &in, &len_in, &out, &len_out);
 	g_free(normalizedWord);
-	if ((size_t)-1 == result)
-		return NULL;
+	if (static_cast<size_t>(-1) == result)
+		return nullptr;
 
 	*out = '\0';
 	char **sugMS;
@@ -148,8 +157,8 @@ MySpellChecker::suggestWord(const char* const utf8Word, size_t len, size_t *nsug
 			len_in = strlen(in);
 			len_out = MAXWORDLEN;
 			char *word = g_new0(char, len_out + 1);
-			out = reinterpret_cast<char *>(word);
-			if ((size_t)-1 == g_iconv(m_translate_out, &in, &len_in, &out, &len_out)) {
+			out = word;
+			if (static_cast<size_t>(-1) == g_iconv(m_translate_out, &in, &len_in, &out, &len_out)) {
 				for (size_t j = i; j < *nsug; j++)
 					free(sugMS[j]);
 				free(sugMS);
@@ -165,7 +174,7 @@ MySpellChecker::suggestWord(const char* const utf8Word, size_t len, size_t *nsug
 		return sug;
 	}
 	else
-		return 0;
+		return nullptr;
 }
 
 static GSList *
@@ -180,11 +189,11 @@ myspell_checker_get_dictionary_dirs (EnchantBroker * broker)
 		
 		for (iter = config_dirs; iter; iter = iter->next)
 			{
-				dirs = g_slist_append (dirs, g_build_filename ((const gchar *)iter->data, 
-									       "myspell", NULL));
+				dirs = g_slist_append (dirs, g_build_filename (static_cast<const gchar *>(iter->data), 
+									       "myspell", nullptr));
 			}
 
-		g_slist_foreach (config_dirs, (GFunc)g_free, NULL);
+		g_slist_foreach (config_dirs, myspell_checker_free_helper, nullptr);
 		g_slist_free (config_dirs);
 	}
 
@@ -194,7 +203,7 @@ myspell_checker_get_dictionary_dirs (EnchantBroker * broker)
 
 		for (iter = system_data_dirs; *iter; iter++)
 			{
-				dirs = g_slist_append (dirs, g_build_filename (*iter, "myspell", "dicts", NULL));
+				dirs = g_slist_append (dirs, g_build_filename (*iter, "myspell", "dicts", nullptr));
 			}
 	}
 
@@ -202,7 +211,7 @@ myspell_checker_get_dictionary_dirs (EnchantBroker * broker)
 	char * enchant_prefix = enchant_get_prefix_dir();
 	if(enchant_prefix)
 		{
-			char * myspell_prefix = g_build_filename(enchant_prefix, "share", "enchant", "myspell", NULL);
+			char * myspell_prefix = g_build_filename(enchant_prefix, "share", "enchant", "myspell", nullptr);
 			g_free(enchant_prefix);
 			dirs = g_slist_append (dirs, myspell_prefix);
 		}
@@ -218,10 +227,10 @@ myspell_checker_get_dictionary_dirs (EnchantBroker * broker)
 		
 		for (iter = config_dirs; iter; iter = iter->next)
 			{
-				dirs = g_slist_append (dirs, g_strdup ((const gchar *)iter->data));
+				dirs = g_slist_append (dirs, g_strdup (static_cast<const gchar *>(iter->data)));
 			}
 
-		g_slist_foreach (config_dirs, (GFunc)g_free, NULL);
+		g_slist_foreach (config_dirs, myspell_checker_free_helper, nullptr);
 		g_slist_free (config_dirs);
 	}
 
@@ -246,10 +255,10 @@ s_buildDictionaryDirs (std::vector<std::string> & dirs, EnchantBroker * broker)
 	myspell_dirs = myspell_checker_get_dictionary_dirs (broker);
 	for (iter = myspell_dirs; iter; iter = iter->next)
 		{
-			dirs.push_back ((const char *)iter->data);
+			dirs.push_back (static_cast<const char *>(iter->data));
 		}
 
-	g_slist_foreach (myspell_dirs, (GFunc)g_free, NULL);
+	g_slist_foreach (myspell_dirs, myspell_checker_free_helper, nullptr);
 	g_slist_free (myspell_dirs);
 }
 
@@ -261,10 +270,10 @@ s_buildHashNames (std::vector<std::string> & names, EnchantBroker * broker, cons
 	std::vector<std::string> dirs;
 	s_buildDictionaryDirs (dirs, broker);
 
-	char *dict_dic = g_strconcat(dict, ".dic", NULL);
+	char *dict_dic = g_strconcat(dict, ".dic", nullptr);
 	for (size_t i = 0; i < dirs.size(); i++)
 		{
-			char *tmp = g_build_filename (dirs[i].c_str(), dict_dic, NULL);
+			char *tmp = g_build_filename (dirs[i].c_str(), dict_dic, nullptr);
 			names.push_back (tmp);
 			g_free (tmp);
 		}
@@ -320,13 +329,13 @@ myspell_request_dictionary (EnchantBroker * broker, const char * tag)
 	s_buildDictionaryDirs (dirs, broker);
 
 	for (size_t i = 0; i < dirs.size(); i++) {
-		GDir *dir = g_dir_open (dirs[i].c_str(), 0, NULL);
+		GDir *dir = g_dir_open (dirs[i].c_str(), 0, nullptr);
 		if (dir) {
 			const char *dir_entry;
 			while ((dir_entry = g_dir_read_name (dir)) != NULL) {
 				if (is_plausible_dict_for_tag(dir_entry, tag)) {
 					char *dict = g_build_filename (dirs[i].c_str(), 
-								       dir_entry, NULL);
+								       dir_entry, nullptr);
                     if(s_hasCorrespondingAffFile(dict)){
 			                    g_dir_close (dir);
 					    return dict;
@@ -380,7 +389,7 @@ myspell_dict_suggest (EnchantDict * me, const char *const word,
 {
 	MySpellChecker * checker;
 	
-	checker = (MySpellChecker *) me->user_data;
+	checker = static_cast<MySpellChecker *>(me->user_data);
 	return checker->suggestWord (word, len, out_n_suggs);
 }
 
@@ -389,7 +398,7 @@ myspell_dict_check (EnchantDict * me, const char *const word, size_t len)
 {
 	MySpellChecker * checker;
 	
-	checker = (MySpellChecker *) me->user_data;
+	checker = static_cast<MySpellChecker *>(me->user_data);
 	
 	if (checker->checkWord(word, len))
 		return 0;
@@ -401,12 +410,12 @@ static void
 myspell_provider_enum_dicts (const char * const directory,
 			     std::vector<std::string> & out_dicts)
 {
-	GDir * dir = g_dir_open (directory, 0, NULL);
+	GDir * dir = g_dir_open (directory, 0, nullptr);
 	if (dir) {
 		const char * entry;
 		
 		while ((entry = g_dir_read_name (dir)) != NULL) {
-			char * utf8_entry = g_filename_to_utf8 (entry, -1, NULL, NULL, NULL);
+			char * utf8_entry = g_filename_to_utf8 (entry, -1, nullptr, nullptr, nullptr);
 			if (utf8_entry) {
 				std::string dir_entry (utf8_entry);
 				g_free (utf8_entry);
@@ -419,7 +428,7 @@ myspell_provider_enum_dicts (const char * const directory,
 					{
 						std::string name(dir_entry.substr (0, hit));
 						std::string affFileName(name + ".aff");
-						char * aff = g_build_filename(directory, affFileName.c_str(), NULL);
+						char * aff = g_build_filename(directory, affFileName.c_str(), nullptr);
 						if (g_file_test(aff, G_FILE_TEST_EXISTS))
 						{
 							out_dicts.push_back (dir_entry.substr (0, hit));
@@ -465,7 +474,7 @@ myspell_provider_list_dicts (EnchantProvider * me,
 }
 
 static void
-myspell_provider_free_string_list (EnchantProvider * me, char **str_list)
+myspell_provider_free_string_list (EnchantProvider * me _GL_UNUSED_PARAMETER, char **str_list)
 {
 	g_strfreev (str_list);
 }
@@ -496,7 +505,7 @@ myspell_provider_request_dict(EnchantProvider * me, const char *const tag)
 }
 
 static void
-myspell_provider_dispose_dict (EnchantProvider * me, EnchantDict * dict)
+myspell_provider_dispose_dict (EnchantProvider * me _GL_UNUSED_PARAMETER, EnchantDict * dict)
 {
 	MySpellChecker *checker;
 	
@@ -533,13 +542,13 @@ myspell_provider_dispose (EnchantProvider * me)
 }
 
 static const char *
-myspell_provider_identify (EnchantProvider * me)
+myspell_provider_identify (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "myspell";
 }
 
 static const char *
-myspell_provider_describe (EnchantProvider * me)
+myspell_provider_describe (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "Myspell Provider";
 }
diff --git a/src/pwl.c b/src/pwl.c
index 8c2629b..31f2eaa 100644
--- a/src/pwl.c
+++ b/src/pwl.c
@@ -52,6 +52,8 @@
  *
  */
 
+#include "config.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -63,6 +65,7 @@
 #include <glib.h>
 #include <glib/gstdio.h>
 #include "enchant-provider.h"
+#include "unused-parameter.h"
 
 #include "pwl.h"
 
@@ -758,7 +761,8 @@ static void enchant_pwl_suggest_cb(char* match,EnchantTrieMatcher* matcher)
 
 }
 
-void enchant_pwl_free_string_list(EnchantPWL *pwl, char** string_list)
+void enchant_pwl_free_string_list(EnchantPWL *pwl _GL_UNUSED_PARAMETER,
+				  char** string_list)
 {
 	g_strfreev(string_list);
 }
@@ -794,7 +798,9 @@ static void enchant_trie_free(EnchantTrie* trie)
 	g_free(trie);
 }
 
-static void enchant_trie_free_cb(void* key, void* value, void* data)
+static void enchant_trie_free_cb(void* key _GL_UNUSED_PARAMETER,
+				 void* value,
+				 void* data _GL_UNUSED_PARAMETER)
 {
 	enchant_trie_free((EnchantTrie*) value);
 }
diff --git a/src/uspell/Makefile.am b/src/uspell/Makefile.am
index 8a42796..efe7d80 100644
--- a/src/uspell/Makefile.am
+++ b/src/uspell/Makefile.am
@@ -4,7 +4,7 @@ else
 target_lib =
 endif
 
-AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(USPELL_CFLAGS) $(CXX_WARN_CFLAGS) -D_ENCHANT_BUILD=1
+AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(USPELL_CFLAGS) $(WARN_CXXFLAGS) -D_ENCHANT_BUILD=1
 
 uspell_LTLIBRARIES = $(target_lib)
 uspelldir= $(libdir)/enchant
diff --git a/src/voikko/Makefile.am b/src/voikko/Makefile.am
index 739c36a..3e724ce 100644
--- a/src/voikko/Makefile.am
+++ b/src/voikko/Makefile.am
@@ -4,7 +4,7 @@ else
 target_lib =
 endif
 
-AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(CC_WARN_CFLAGS) $(VOIKKO_CFLAGS) -D_ENCHANT_BUILD=1
+AM_CPPFLAGS = -I$(top_srcdir) $(ISYSTEM)$(top_builddir)/lib $(ISYSTEM)$(top_srcdir)/lib -I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(WARN_CFLAGS) $(VOIKKO_CFLAGS) -D_ENCHANT_BUILD=1
 
 voikko_LTLIBRARIES = $(target_lib)
 voikkodir= $(libdir)/enchant
diff --git a/src/voikko/voikko_provider.c b/src/voikko/voikko_provider.c
index 6cf4c6d..d4a6327 100644
--- a/src/voikko/voikko_provider.c
+++ b/src/voikko/voikko_provider.c
@@ -30,12 +30,15 @@
  * do so, delete this exception statement from your version.
  */
 
+#include "config.h"
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include <glib.h>
 #include <libvoikko/voikko.h>
+#include "unused-parameter.h"
 
 #include "enchant.h"
 #include "enchant-provider.h"
@@ -48,7 +51,7 @@
 ENCHANT_PLUGIN_DECLARE("Voikko")
 
 static int
-voikko_dict_check (EnchantDict * me, const char *const word, size_t len)
+voikko_dict_check (EnchantDict * me, const char *const word, size_t len _GL_UNUSED_PARAMETER)
 {
 	int result;
 	int voikko_handle;
@@ -65,7 +68,7 @@ voikko_dict_check (EnchantDict * me, const char *const word, size_t len)
 
 static char **
 voikko_dict_suggest (EnchantDict * me, const char *const word,
-		     size_t len, size_t * out_n_suggs)
+		     size_t len _GL_UNUSED_PARAMETER, size_t * out_n_suggs)
 {
 	char **sugg_arr;
 	int voikko_handle;
@@ -104,14 +107,14 @@ voikko_provider_request_dict (EnchantProvider * me, const char *const tag)
 }
 
 static void
-voikko_provider_dispose_dict (EnchantProvider * me, EnchantDict * dict)
+voikko_provider_dispose_dict (EnchantProvider * me _GL_UNUSED_PARAMETER, EnchantDict * dict)
 {
 	voikko_terminate((long) dict->user_data);
 	g_free (dict);
 }
 
 static int
-voikko_provider_dictionary_exists (struct str_enchant_provider * me,
+voikko_provider_dictionary_exists (struct str_enchant_provider * me _GL_UNUSED_PARAMETER,
                                    const char *const tag)
 {
 	int voikko_handle;
@@ -130,7 +133,7 @@ voikko_provider_dictionary_exists (struct str_enchant_provider * me,
 
 
 static char **
-voikko_provider_list_dicts (EnchantProvider * me, 
+voikko_provider_list_dicts (EnchantProvider * me _GL_UNUSED_PARAMETER, 
 			    size_t * out_n_dicts)
 {
 	char ** out_list = NULL;
@@ -148,7 +151,8 @@ voikko_provider_list_dicts (EnchantProvider * me,
 }
 
 static void
-voikko_provider_free_string_list (EnchantProvider * me, char **str_list)
+voikko_provider_free_string_list (EnchantProvider * me _GL_UNUSED_PARAMETER,
+				  char **str_list)
 {
 	g_strfreev (str_list);
 }
@@ -160,13 +164,13 @@ voikko_provider_dispose (EnchantProvider * me)
 }
 
 static const char *
-voikko_provider_identify (EnchantProvider * me)
+voikko_provider_identify (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "voikko";
 }
 
 static const char *
-voikko_provider_describe (EnchantProvider * me)
+voikko_provider_describe (EnchantProvider * me _GL_UNUSED_PARAMETER)
 {
 	return "Voikko Provider";
 }
diff --git a/src/zemberek/Makefile.am b/src/zemberek/Makefile.am
index 6e30006..c347a53 100644
--- a/src/zemberek/Makefile.am
+++ b/src/zemberek/Makefile.am
@@ -4,7 +4,7 @@ else
 target_lib =
 endif
 
-AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(ZEMBEREK_CFLAGS) $(CXX_WARN_CFLAGS) -D_ENCHANT_BUILD=1
+AM_CPPFLAGS=-I$(top_srcdir)/src $(ENCHANT_CFLAGS) $(ZEMBEREK_CFLAGS) $(WARN_CXXFLAGS) -D_ENCHANT_BUILD=1
 
 zemberek_LTLIBRARIES = $(target_lib)
 zemberekdir= $(libdir)/enchant