Move gdb/warning.m4 to gdbsupport

This file is used by gdbsupport, gdbserver and gdb, so I think it
belongs in gdbsupport.  Move it there and update the references the
various acinclude.m4 files.

gdbsupport/ChangeLog:

	* warning.m4: Move here, from gdb/warning.m4.
	* acinclude.m4: Update warning.m4 path.
	* Makefile.in: Re-generate.

gdbserver/ChangeLog:

	* acinclude.m4: Update warning.m4 path.

gdb/ChangeLog:

	* acinclude: Update warning.m4 path.
	* warning.m4: Move to gdbsupport.

4 files changed, 167 insertions, 2 deletions

diff --git a/gdbsupport/ChangeLog b/gdbsupport/ChangeLog
index 4a820acf527..f03bb34bac1 100644
--- a/gdbsupport/ChangeLog
+++ b/gdbsupport/ChangeLog
@@ -1,5 +1,11 @@
 2020-02-11  Simon Marchi  <simon.marchi@efficios.com>
 
+	* warning.m4: Move here, from gdb/warning.m4.
+	* acinclude.m4: Update warning.m4 path.
+	* Makefile.in: Re-generate.
+
+2020-02-11  Simon Marchi  <simon.marchi@efficios.com>
+
 	* acinclude.m4: Include ../gdb/warning.m4.
 	* configure.ac: Use AM_GDB_WARNINGS.
 	* Makefile.am: Set AM_CFLAGS to WARN_CFLAGS and WERROR_CFLAGS.
diff --git a/gdbsupport/Makefile.in b/gdbsupport/Makefile.in
index 91164175bc0..be4d5354531 100644
--- a/gdbsupport/Makefile.in
+++ b/gdbsupport/Makefile.in
@@ -124,7 +124,7 @@ am__aclocal_m4_deps = $(top_srcdir)/../config/codeset.m4 \
 	$(top_srcdir)/../gdb/ax_cxx_compile_stdcxx.m4 \
 	$(top_srcdir)/../gdb/libiberty.m4 \
 	$(top_srcdir)/../gdb/selftest.m4 \
-	$(top_srcdir)/../gdb/ptrace.m4 $(top_srcdir)/../gdb/warning.m4 \
+	$(top_srcdir)/../gdb/ptrace.m4 $(top_srcdir)/warning.m4 \
 	$(top_srcdir)/configure.ac
 am__configure_deps = $(am__aclocal_m4_deps) $(CONFIGURE_DEPENDENCIES) \
 	$(ACLOCAL_M4)
diff --git a/gdbsupport/acinclude.m4 b/gdbsupport/acinclude.m4
index 3598b201b94..d638ebcb543 100644
--- a/gdbsupport/acinclude.m4
+++ b/gdbsupport/acinclude.m4
@@ -7,4 +7,4 @@ m4_include([../gdb/selftest.m4])
 m4_include([../gdb/ptrace.m4])
 
 dnl This gets AM_GDB_WARNINGS.
-m4_include(../gdb/warning.m4)
+m4_include(warning.m4)
diff --git a/gdbsupport/warning.m4 b/gdbsupport/warning.m4
new file mode 100644
index 00000000000..e2b8a43ddbd
--- /dev/null
+++ b/gdbsupport/warning.m4
@@ -0,0 +1,159 @@
+dnl Autoconf configure script for GDB, the GNU debugger.
+dnl Copyright (C) 1995-2020 Free Software Foundation, Inc.
+dnl
+dnl This file is part of GDB.
+dnl
+dnl This program is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 3 of the License, or
+dnl (at your option) any later version.
+dnl
+dnl This program is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+dnl GNU General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+AC_DEFUN([AM_GDB_WARNINGS],[
+AC_ARG_ENABLE(werror,
+  AS_HELP_STRING([--enable-werror], [treat compile warnings as errors]),
+  [case "${enableval}" in
+     yes | y) ERROR_ON_WARNING="yes" ;;
+     no | n)  ERROR_ON_WARNING="no" ;;
+     *) AC_MSG_ERROR(bad value ${enableval} for --enable-werror) ;;
+   esac])
+
+# Enable -Werror by default when using gcc.  Turn it off for releases.
+if test "${GCC}" = yes -a -z "${ERROR_ON_WARNING}" && $development; then
+    ERROR_ON_WARNING=yes
+fi
+
+WERROR_CFLAGS=""
+if test "${ERROR_ON_WARNING}" = yes ; then
+    WERROR_CFLAGS="-Werror"
+fi
+
+# The options we'll try to enable.
+build_warnings="-Wall -Wpointer-arith \
+-Wno-unused -Wunused-value -Wunused-variable -Wunused-function \
+-Wno-switch -Wno-char-subscripts \
+-Wempty-body -Wunused-but-set-parameter -Wunused-but-set-variable \
+-Wno-sign-compare -Wno-error=maybe-uninitialized \
+-Wno-mismatched-tags \
+-Wno-error=deprecated-register \
+-Wsuggest-override \
+-Wimplicit-fallthrough=3 \
+-Wduplicated-cond \
+-Wshadow=local \
+-Wdeprecated-copy \
+-Wdeprecated-copy-dtor \
+-Wredundant-move \
+-Wmissing-declarations"
+
+case "${host}" in
+  *-*-mingw32*)
+    # Enable -Wno-format by default when using gcc on mingw since many
+    # GCC versions complain about %I64.
+    build_warnings="$build_warnings -Wno-format" ;;
+  *-*-solaris*)
+    # Solaris 11.4 <python2.7/ceval.h> uses #pragma no_inline that GCC
+    # doesn't understand.
+    build_warnings="$build_warnings -Wno-unknown-pragmas"
+    # Solaris 11 <unistd.h> marks vfork deprecated.
+    build_warnings="$build_warnings -Wno-deprecated-declarations" ;;
+  *)
+    # Note that gcc requires -Wformat for -Wformat-nonliteral to work,
+    # but there's a special case for this below.
+    build_warnings="$build_warnings -Wformat-nonliteral" ;;
+esac
+
+AC_ARG_ENABLE(build-warnings,
+AS_HELP_STRING([--enable-build-warnings], [enable build-time compiler warnings if gcc is used]),
+[case "${enableval}" in
+  yes)	;;
+  no)	build_warnings="-w";;
+  ,*)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
+        build_warnings="${build_warnings} ${t}";;
+  *,)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
+        build_warnings="${t} ${build_warnings}";;
+  *)    build_warnings=`echo "${enableval}" | sed -e "s/,/ /g"`;;
+esac
+if test x"$silent" != x"yes" && test x"$build_warnings" != x""; then
+  echo "Setting compiler warning flags = $build_warnings" 6>&1
+fi])dnl
+AC_ARG_ENABLE(gdb-build-warnings,
+AS_HELP_STRING([--enable-gdb-build-warnings], [enable GDB specific build-time compiler warnings if gcc is used]),
+[case "${enableval}" in
+  yes)	;;
+  no)	build_warnings="-w";;
+  ,*)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
+        build_warnings="${build_warnings} ${t}";;
+  *,)   t=`echo "${enableval}" | sed -e "s/,/ /g"`
+        build_warnings="${t} ${build_warnings}";;
+  *)    build_warnings=`echo "${enableval}" | sed -e "s/,/ /g"`;;
+esac
+if test x"$silent" != x"yes" && test x"$build_warnings" != x""; then
+  echo "Setting GDB specific compiler warning flags = $build_warnings" 6>&1
+fi])dnl
+
+# The set of warnings supported by a C++ compiler is not the same as
+# of the C compiler.
+AC_LANG_PUSH([C++])
+
+WARN_CFLAGS=""
+if test "x${build_warnings}" != x -a "x$GCC" = xyes
+then
+    AC_MSG_CHECKING(compiler warning flags)
+    # Separate out the -Werror flag as some files just cannot be
+    # compiled with it enabled.
+    for w in ${build_warnings}; do
+	# GCC does not complain about -Wno-unknown-warning.  Invert
+	# and test -Wunknown-warning instead.
+	case $w in
+	-Wno-*)
+		wtest=`echo $w | sed 's/-Wno-/-W/g'` ;;
+        -Wformat-nonliteral)
+		# gcc requires -Wformat before -Wformat-nonliteral
+		# will work, so stick them together.
+		w="-Wformat $w"
+		wtest="$w"
+		;;
+	*)
+		wtest=$w ;;
+	esac
+
+	case $w in
+	-Werr*) WERROR_CFLAGS=-Werror ;;
+	*)
+	    # Check whether GCC accepts it.
+	    saved_CFLAGS="$CFLAGS"
+	    CFLAGS="$CFLAGS -Werror $wtest"
+	    saved_CXXFLAGS="$CXXFLAGS"
+	    CXXFLAGS="$CXXFLAGS -Werror $wtest"
+	    if test "x$w" = "x-Wunused-variable"; then
+	      # Check for https://gcc.gnu.org/bugzilla/show_bug.cgi?id=38958,
+	      # fixed in GCC 4.9.  This test is derived from the gdb
+	      # source code that triggered this bug in GCC.
+	      AC_TRY_COMPILE(
+	        [struct scoped_restore_base {};
+                 struct scoped_restore_tmpl : public scoped_restore_base {
+		   ~scoped_restore_tmpl() {}
+		 };],
+		[const scoped_restore_base &b = scoped_restore_tmpl();],
+		WARN_CFLAGS="${WARN_CFLAGS} $w",)
+	    else
+	      AC_TRY_COMPILE([],[],WARN_CFLAGS="${WARN_CFLAGS} $w",)
+	    fi
+	    CFLAGS="$saved_CFLAGS"
+	    CXXFLAGS="$saved_CXXFLAGS"
+	esac
+    done
+    AC_MSG_RESULT(${WARN_CFLAGS} ${WERROR_CFLAGS})
+fi
+AC_SUBST(WARN_CFLAGS)
+AC_SUBST(WERROR_CFLAGS)
+
+AC_LANG_POP([C++])
+])