build: require GNU make in order to run the maintainer checks

This is not a real regression in portability, since most maintainer
check rules already assumed GNU grep, and were anyway only meant to
run on the developers' systems (where we can safely assume the
presence of GNU make).

This change will allow us to take advantage, in future changes, of
more GNU make features, thus simplifying or optimizing some of our
maintainer rules.

* GNUmakefile: New, including 'Makefile' and 'syntax-checks.mk'.
* configure.ac (AC_CONFIG_LINKS): Link it in the builddir.
* Makefile.am (EXTRA_DIST): Distribute 'GNUmakefile' and
'syntax-checks.mk'.
Move all syntax-check rules and auxiliary variables into ...
* syntax-checks.mk: ... this new file, with some adjustments.

4 files changed, 610 insertions, 568 deletions

diff --git a/GNUmakefile b/GNUmakefile
new file mode 100644
index 000000000..134e74323
--- /dev/null
+++ b/GNUmakefile
@@ -0,0 +1,19 @@
+# Maintainer makefile for Automake.  Requires GNU make.
+
+# Copyright (C) 2012 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+include ./Makefile
+include $(srcdir)/syntax-checks.mk
diff --git a/Makefile.am b/Makefile.am
index cdd40f284..20a3584d7 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -33,6 +33,8 @@ AUTOMAKESOURCES = automake.in aclocal.in
 TAGS_FILES = $(AUTOMAKESOURCES)
 
 EXTRA_DIST = \
+  GNUmakefile \
+  syntax-checks.mk \
   HACKING \
   ChangeLog.96 \
   ChangeLog.98 \
@@ -193,574 +195,6 @@ clean-local: clean-coverage
 .PHONY: check-coverage recheck-coverage check-coverage-run \
 	recheck-coverage-run check-coverage-report clean-coverage
 
-# We also have to take into account VPATH builds (where some generated
-# tests might be in `$(builddir)' rather than in `$(srcdir)'), TAP-based
-# tests script (which have a `.tap' extension) and helper scripts used
-# by other test cases (which have a `.sh' extension).
-xtests = \
-  `if test $(srcdir) = .; then \
-     dirs=.; \
-   else \
-     dirs='$(srcdir) .'; \
-   fi; \
-   for d in $$dirs; do \
-     for s in test tap sh; do \
-       ls $$d/tests/*.$$s 2>/dev/null; \
-     done; \
-   done | sort`
-
-ams = `find $(srcdir) -name '*.am'`
-
-# Some simple checks, and then ordinary check.  These are only really
-# guaranteed to work on my machine.
-syntax_check_rules = \
-sc_test_names \
-sc_diff_automake_in_automake \
-sc_diff_aclocal_in_automake \
-sc_perl_syntax \
-sc_no_brace_variable_expansions \
-sc_rm_minus_f \
-sc_no_for_variable_in_macro \
-sc_mkinstalldirs \
-sc_pre_normal_post_install_uninstall \
-sc_perl_no_undef \
-sc_perl_no_split_regex_space \
-sc_cd_in_backquotes \
-sc_cd_relative_dir \
-sc_perl_at_uscore_in_scalar_context \
-sc_perl_local_no_parens \
-sc_perl_local \
-sc_AMDEP_TRUE_in_automake_in \
-sc_tests_make_without_am_makeflags \
-sc_tests_obsolete_variables \
-sc_tests_plain_make \
-sc_tests_plain_autoconf \
-sc_tests_plain_autoupdate \
-sc_tests_plain_automake \
-sc_tests_plain_autom4te \
-sc_tests_plain_autoheader \
-sc_tests_plain_autoreconf \
-sc_tests_here_document_format \
-sc_tests_Exit_not_exit \
-sc_tests_automake_fails \
-sc_tests_plain_aclocal \
-sc_tests_plain_perl \
-sc_tests_required_after_defs \
-sc_tests_tap_plan \
-sc_tests_overriding_macros_on_cmdline \
-sc_tests_plain_sleep \
-sc_tests_plain_egrep_fgrep \
-sc_tests_PATH_SEPARATOR \
-sc_tests_logs_duplicate_prefixes \
-sc_tests_makefile_variable_order \
-sc_mkdir_p \
-sc_perl_at_substs \
-sc_unquoted_DESTDIR \
-sc_tabs_in_texi \
-sc_at_in_texi
-
-$(syntax_check_rules): automake aclocal
-maintainer-check: $(syntax_check_rules)
-.PHONY: maintainer-check $(syntax_check_rules)
-
-## Check that the list of tests given in the Makefile is equal to the
-## list of all test scripts in the Automake testsuite.
-.PHONY: maintainer-check-list-of-tests
-maintainer-check-list-of-tests:
-	$(am__cd) tests && $(MAKE) $(AM_MAKEFLAGS) $@
-maintainer-check: maintainer-check-list-of-tests
-
-## Look for test whose names can cause spurious failures when used as
-## first argument to AC_INIT (chiefly because they might contain an
-## m4/m4sugar builtin or macro name).
-m4_builtins = \
-  __gnu__ \
-  __unix__ \
-  bpatsubst \
-  bregexp \
-  builtin \
-  changecom \
-  changequote \
-  changeword \
-  debugfile \
-  debugmode \
-  decr \
-  define \
-  defn \
-  divert \
-  divnum \
-  dnl \
-  dumpdef \
-  errprint \
-  esyscmd \
-  eval \
-  format \
-  ifdef \
-  ifelse \
-  include \
-  incr \
-  index \
-  indir \
-  len \
-  m4exit \
-  m4wrap \
-  maketemp \
-  mkstemp \
-  patsubst \
-  popdef \
-  pushdef \
-  regexp \
-  shift \
-  sinclude \
-  substr \
-  symbols \
-  syscmd \
-  sysval \
-  traceoff \
-  traceon \
-  translit \
-  undefine \
-  undivert
-sc_test_names:
-	@m4_builtin_rx=`echo $(m4_builtins) | sed 's/ /|/g'`; \
-	 m4_macro_rx="\\<($$m4_builtin_rx)\\>|\\<_?(A[CUMHS]|m4)_"; \
-	 if { \
-	   for t in $(xtests); do echo $$t; done \
-	     | LC_ALL=C grep -E "$$m4_macro_rx"; \
-	 }; then \
-	   echo "the names of the tests above can be problematic" 1>&2; \
-	   echo "Avoid test names that contain names of m4 macros" 1>&2; \
-	   exit 1; \
-	 fi
-
-## These check avoids accidental configure substitutions in the source.
-## There are exactly 9 lines that should be modified from automake.in to
-## automake, and 10 lines that should be modified from aclocal.in to
-## aclocal; these wors out to 32 and 34 lines of diffs, respectively.
-sc_diff_automake_in_automake:
-	@if test `diff $(srcdir)/automake.in automake | wc -l` -ne 32; then \
-	  echo "found too many diffs between automake.in and automake" 1>&2; \
-	  diff -c $(srcdir)/automake.in automake; \
-	  exit 1; \
-	fi
-sc_diff_aclocal_in_aclocal:
-	@if test `diff $(srcdir)/aclocal.in aclocal | wc -l` -ne 34; then \
-	  echo "found too many diffs between aclocal.in and aclocal" 1>&2; \
-	  diff -c $(srcdir)/aclocal.in aclocal; \
-	  exit 1; \
-	fi
-
-## Syntax check with default Perl (on my machine, Perl 5).
-sc_perl_syntax:
-	@perllibdir="./lib$(PATH_SEPARATOR)$(srcdir)/lib" $(PERL) -c -w automake
-	@perllibdir="./lib$(PATH_SEPARATOR)$(srcdir)/lib" $(PERL) -c -w aclocal
-
-## expect no instances of '${...}'.  However, $${...} is ok, since that
-## is a shell construct, not a Makefile construct.
-sc_no_brace_variable_expansions:
-	@if grep -F '$${' $(ams) | grep -F -v '$$$$'; then \
-	  echo "Found too many uses of '\$${' in the lines above." 1>&2; \
-	  exit 1;				\
-	else :; fi
-
-## Make sure `rm' is called with `-f'.
-sc_rm_minus_f:
-	@if grep -v '^#' $(ams) $(xtests) \
-	   | grep -E '\<rm ([^-]|\-[^f ]*\>)'; \
-	then \
-	  echo "Suspicious 'rm' invocation." 1>&2; \
-	  exit 1;				\
-	else :; fi
-
-## Never use something like `for file in $(FILES)', this doesn't work
-## if FILES is empty or if it contains shell meta characters (e.g. $ is
-## commonly used in Java filenames).
-sc_no_for_variable_in_macro:
-	@if grep 'for .* in \$$(' $(ams); then \
-	  echo 'Use "list=$$(mumble); for var in $$$$list".' 1>&2 ; \
-	  exit 1; \
-	else :; fi
-
-## Make sure all invocations of mkinstalldirs are correct.
-sc_mkinstalldirs:
-	@if grep -n 'mkinstalldirs' $(ams) | \
-	      grep -F -v '$$(mkinstalldirs)'; then \
-	  echo "Found incorrect use of mkinstalldirs in the lines above" 1>&2; \
-	  exit 1; \
-	else :; fi
-
-## Make sure all calls to PRE/NORMAL/POST_INSTALL/UNINSTALL
-sc_pre_normal_post_install_uninstall:
-	@if grep -E -n '\((PRE|NORMAL|POST)_(|UN)INSTALL\)' $(ams) | \
-	      grep -v ':##' | grep -v ':	@\$$('; then \
-	  echo "Found incorrect use of PRE/NORMAL/POST_INSTALL/UNINSTALL in the lines above" 1>&2; \
-	  exit 1; \
-	else :; fi
-
-## We never want to use "undef", only "delete", but for $/.
-sc_perl_no_undef:
-	@if grep -n -w 'undef ' $(srcdir)/automake.in | \
-	      grep -F -v 'undef $$/'; then \
-	  echo "Found undef in automake.in; use delete instead" 1>&2; \
-	  exit 1; \
-	fi
-
-## We never want split (/ /,...), only split (' ', ...).
-sc_perl_no_split_regex_space:
-	@if grep -n 'split (/ /' $(srcdir)/automake.in; then \
-	  echo "Found bad split in the lines above." 1>&2; \
-	  exit 1; \
-	fi
-
-## Look for cd within backquotes
-sc_cd_in_backquotes:
-	@if grep -n '^[^#]*` *cd ' $(srcdir)/automake.in $(ams); then \
-	  echo "Consider using \$$(am__cd) in the lines above." 1>&2; \
-	  exit 1; \
-	fi
-
-## Look for cd to a relative directory (may be influenced by CDPATH).
-## Skip some known directories that are OK.
-sc_cd_relative_dir:
-	@if grep -n '^[^#]*cd ' $(srcdir)/automake.in $(ams) | \
-	      grep -v 'echo.*cd ' | \
-	      grep -v 'am__cd =' | \
-	      grep -v '^[^#]*cd [./]' | \
-	      grep -v '^[^#]*cd \$$(top_builddir)' | \
-	      grep -v '^[^#]*cd "\$$\$$am__cwd' | \
-	      grep -v '^[^#]*cd \$$(abs' | \
-	      grep -v '^[^#]*cd "\$$(DESTDIR)'; then \
-	  echo "Consider using \$$(am__cd) in the lines above." 1>&2; \
-	  exit 1; \
-	fi
-
-## Using @_ in a scalar context is most probably a programming error.
-sc_perl_at_uscore_in_scalar_context:
-	@if grep -Hn '[^@_A-Za-z0-9][_A-Za-z0-9]*[^) ] *= *@_' $(srcdir)/automake.in; then \
-	  echo "Using @_ in a scalar context in the lines above." 1>&2; \
-	  exit 1; \
-	fi
-
-## Forbid using parens with `local' to ease counting.
-sc_perl_local_no_parens:
-	@if grep '^[ \t]*local *(' $(srcdir)/automake.in; then \
-	  echo "Don't use \`local' with parens: use several \`local' above." >&2; \
-	  exit 1; \
-	fi
-
-## Allow only few variables to be localized in Automake.
-sc_perl_local:
-	@if egrep -v '^[ \t]*local \$$[_~]( *=|;)' $(srcdir)/automake.in | \
-	        grep '^[ \t]*local [^*]'; then \
-	  echo "Please avoid \`local'." 1>&2; \
-	  exit 1; \
-	fi
-
-## Don't let AMDEP_TRUE substitution appear in automake.in.
-sc_AMDEP_TRUE_in_automake_in:
-	@if grep '@AMDEP''_TRUE@' $(srcdir)/automake.in; then \
-	  echo "Don't put AMDEP_TRUE substitution in automake.in" 1>&2; \
-	  exit 1; \
-	fi
-
-## Recursive make invocations should always pass $(AM_MAKEFLAGS)
-## to $(MAKE), for portability to non-GNU make.
-sc_tests_make_without_am_makeflags:
-	@if grep '^[^#].*(MAKE) ' $(ams) $(srcdir)/automake.in | \
-		grep -v 'AM_MAKEFLAGS'; then \
-	  echo 'Use $$(MAKE) $$(AM_MAKEFLAGS).' 1>&2; \
-	  exit 1; \
-	fi
-
-## Look out for some obsolete variables.
-sc_tests_obsolete_variables:
-	@vars=" \
-	  using_tap \
-	  parallel_tests \
-	  test_prefer_config_shell \
-	  original_AUTOMAKE \
-	  original_ACLOCAL \
-	"; \
-	seen=""; \
-	for v in $$vars; do \
-	  if grep -E "\b$$v\b" \
-	    $(xtests) $(srcdir)/tests/defs \
-	    $(srcdir)/tests/defs-static.in \
-	  ; then \
-	    seen="$$seen $$v"; \
-	  fi; \
-	done; \
-	if test -n "$$seen"; then \
-	  for v in $$seen; do \
-	    echo "Variable '$$v' is obsolete, use 'am_$$v' instead." 1>&2; \
-	  done; \
-	  exit 1; \
-	else :; fi
-
-## Tests should never call make directly.
-sc_tests_plain_make:
-	@if grep -v '^#' $(xtests) | $(EGREP) ':[ 	]*make( |$$)'; then \
-	  echo 'Do not run "make" in the above tests.  Use "$$MAKE" instead.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Tests should never call autoconf directly.
-sc_tests_plain_autoconf:
-	@if grep -v '^#' $(xtests) | grep ':[	]*autoconf\>'; then \
-	  echo 'Do not run "autoconf" in the above tests.  Use "$$AUTOCONF" instead.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Tests should never call autoupdate directly.
-sc_tests_plain_autoupdate:
-	@if grep -v '^#' $(xtests) | grep ':[	]*autoupdate\>'; then \
-	  echo 'Do not run "autoupdate" in the above tests.  Use "$$AUTOUPDATE" instead.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Tests should never call automake directly.
-sc_tests_plain_automake:
-	@if grep -v '^#' $(xtests) | grep -E ':[	]*automake\>([^:]|$$)'; then \
-	  echo 'Do not run "automake" in the above tests.  Use "$$AUTOMAKE" instead.' 1>&2;  \
-	  exit 1; \
-	fi
-
-## Tests should never call autoheader directly.
-sc_tests_plain_autoheader:
-	@if grep -v '^#' $(xtests) | grep ':[	]*autoheader\>'; then \
-	  echo 'Do not run "autoheader" in the above tests.  Use "$$AUTOHEADER" instead.' 1>&2;  \
-	  exit 1; \
-	fi
-
-## Tests should never call autoreconf directly.
-sc_tests_plain_autoreconf:
-	@if grep -v '^#' $(xtests) | grep ':[	]*autoreconf\>'; then \
-	  echo 'Do not run "autoreconf" in the above tests.  Use "$$AUTORECONF" instead.' 1>&2;  \
-	  exit 1; \
-	fi
-
-## Tests should never call autom4te directly.
-sc_tests_plain_autom4te:
-	@if grep -v '^#' $(xtests) | grep ':[	]*autom4te\>'; then \
-	  echo 'Do not run "autom4te" in the above tests.  Use "$$AUTOM4TE" instead.' 1>&2;  \
-	  exit 1; \
-	fi
-
-## Tests should only use END and EOF for here documents
-## (so that the next test is effective).
-sc_tests_here_document_format:
-	@if grep '<<' $(xtests) | grep -v 'END' | grep -v 'EOF'; then \
-	  echo 'Use here documents with "END" and "EOF" only, for greppability.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Tests should never call exit directly, but use Exit.
-## This is so that the exit status is transported correctly across the 0 trap.
-## Ignore comments, testsuite self tests, and one perl line in ext2.test.
-sc_tests_Exit_not_exit:
-	@found=false; for file in $(xtests); do \
-	  case $$file in */self-check-*) continue;; esac; \
-	  res=`sed -n -e '/^#/d; /^\$$PERL/d' -e '/<<.*END/,/^END/b' \
-		      -e '/<<.*EOF/,/^EOF/b' -e '/exit [$$0-9]/p' $$file`; \
-	  if test -n "$$res"; then \
-	    echo "$$file:$$res"; \
-	    found=true; \
-	  fi; \
-	done; \
-	if $$found; then \
-	  echo 'Do not call plain "exit", use "Exit" instead, in above tests.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Use AUTOMAKE_fails when appropriate
-sc_tests_automake_fails:
-	@if grep -v '^#' $(xtests) | grep '\$$AUTOMAKE.*&&.*[eE]xit'; then \
-	  echo 'Use AUTOMAKE_fails + grep to catch automake failures in the above tests.' 1>&2;  \
-	  exit 1; \
-	fi
-
-## Tests should never call aclocal directly.
-sc_tests_plain_aclocal:
-	@if grep -v '^#' $(xtests) | grep ':[	]*aclocal\>'; then \
-	  echo 'Do not run "aclocal" in the above tests.  Use "$$ACLOCAL" instead.' 1>&2;  \
-	  exit 1; \
-	fi
-
-## Tests should never call perl directly.
-sc_tests_plain_perl:
-	@if grep -v '^#' $(xtests) | grep ':[	]*perl\>'; then \
-	  echo 'Do not run "perl" in the above tests.  Use "$$PERL" instead.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Setting `required' after sourcing `./defs' is a bug.
-sc_tests_required_after_defs:
-	@for file in $(xtests); do \
-	  if out=`sed -n '/defs/,$${/required=/p;}' $$file`; test -n "$$out"; then \
-	    echo 'Do not set "required" after sourcing "defs" in '"$$file: $$out" 1>&2; \
-	    exit 1; \
-	  fi; \
-	done
-
-## TAP-based test scripts should not forget to declare a TAP plan.  In
-## case it is not known in advance how many tests will be run, a "lazy"
-## plan can be used; but its use should be deliberate, explicitly declared
-## with a "plan_ later" call, rather than the result of an oversight.
-## This check helps to ensure this is indeed the case.
-sc_tests_tap_plan:
-	@with_plan=`grep -l '^ *plan_ ' $(srcdir)/tests/*.tap`; \
-	 with_plan=`echo $$with_plan`; \
-	 ok=:; \
-	 for t in $(srcdir)/tests/*.tap; do \
-	   case " $$with_plan " in *" $$t "*) continue;; esac; \
-## It's ok for an *auto-generated* test sourcing an hand-written one not
-## to declare a TAP plan: that will be done by the sourced test.
-	   case $$t in \
-	     *-w.tap) \
-	       t2=`echo $$t | sed -e 's|.*/||' -e 's/-w\.tap$$/.tap/'` \
-	         && grep -E "^ *\\.  *[^ 	]*/$$t2\\b" $$t >/dev/null \
-	         && continue || : ;; \
-	   esac; \
-	   ok=false; echo $$t; \
-	 done; \
-	 $$ok || { \
-	  echo 'The tests above do not declare a TAP plan.' 1>&2; \
-	  exit 1; \
-	 }
-
-## Overriding a Makefile macro on the command line is not portable when
-## recursive targets are used.  Better use an envvar.  SHELL is an
-## exception, POSIX says it can't come from the environment.  V, DESTDIR,
-## DISTCHECK_CONFIGURE_FLAGS and DISABLE_HARD_ERRORS are exceptions, too,
-## as package authors are urged not to initialize them anywhere.
-sc_tests_overriding_macros_on_cmdline:
-	@if grep -E '\$$MAKE .*(SHELL=.*=|=.*SHELL=)' $(xtests); then \
-	  echo 'Rewrite "$$MAKE foo=bar SHELL=$$SHELL" as "foo=bar $$MAKE -e SHELL=$$SHELL"' 1>&2; \
-	  echo ' in the above lines, it is more portable.' 1>&2; \
-	  exit 1; \
-	fi
-## Also try to account for usages like "$MAKE || st=$?".
-	@if sed -e 's/ || .*//' -e 's/ && .*//' \
-	        -e 's/ DESTDIR=[^ ]*/ /' -e 's/ SHELL=[^ ]*/ /' \
-	        -e 's/ V=[^ ]*/ /' -e 's/ DISABLE_HARD_ERRORS=[^ ]*/ /' \
-## DISTCHECK_CONFIGURE_FLAGS is allowed to contain whitespace in its
-## definition, so the more complex substitutions below.
-	        -e "s/ DISTCHECK_CONFIGURE_FLAGS='[^']*'/ /" \
-		-e 's/ DISTCHECK_CONFIGURE_FLAGS="[^"]*"/ /' \
-		-e 's/ DISTCHECK_CONFIGURE_FLAGS=[^ ]/ /' \
-	      $(xtests) | grep '\$$MAKE .*='; then \
-	  echo 'Rewrite "$$MAKE foo=bar" as "foo=bar $$MAKE -e" in the above lines,' 1>&2; \
-	  echo 'it is more portable.' 1>&2; \
-	  exit 1; \
-	fi
-	@if grep 'SHELL=.*\$$MAKE' $(xtests); then \
-	  echo '$$MAKE ignores the SHELL envvar, use "$$MAKE SHELL=$$SHELL" in' 1>&2; \
-	  echo 'the above lines.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Never use `sleep 1' to create files with different timestamps.
-## Use `$sleep' instead.  Some filesystems (e.g., Windows') have only
-## a 2sec resolution.
-sc_tests_plain_sleep:
-	@if grep -E '\bsleep +[12345]\b' $(xtests); then \
-	  echo 'Do not use "sleep x" in the above tests.  Use "$$sleep" instead.' 1>&2; \
-	  exit 1; \
-	fi
-
-## fgrep and egrep are not required by POSIX.
-sc_tests_plain_egrep_fgrep:
-	@if grep -E '\b[ef]grep\b' $(xtests) ; then \
-	  echo 'Do not use egrep or fgrep in test cases.  Use $$FGREP or $$EGREP.' 1>&2; \
-	  exit 1; \
-	fi
-	@if grep -E '\b[ef]grep\b' $(ams) $(srcdir)/m4/*.m4; then \
-	  echo 'Do not use egrep or fgrep in the above files, they are not portable.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Rule to ensure that the testsuite has been run before.  We don't depend on `check'
-## here, because that would be very wasteful in the common case.  We could run
-## `make check RECHECK_LOGS=' and avoid toplevel races with AM_RECURSIVE_TARGETS.
-## Suggest keeping test directories around for greppability of the Makefile.in files.
-sc_ensure_testsuite_has_run:
-	@if test ! -f tests/test-suite.log; then \
-	  echo "Run \`env keep_testdirs=yes make check' before \`maintainer-check'" >&2; \
-	  exit 1; \
-	fi
-.PHONY: sc_ensure_testsuite_has_run
-
-## Ensure our warning and error messages do not contain duplicate 'warning:' prefixes.
-## This test actually depends on the testsuite having been run before.
-sc_tests_logs_duplicate_prefixes: sc_ensure_testsuite_has_run
-	@if grep -E '(warning|error):.*(warning|error):' tests/*.log; then \
-	  echo 'Duplicate warning/error message prefixes seen in above tests.' >&2; \
-	  exit 1; \
-	fi
-
-## Ensure variables are listed before rules in Makefile.in files we generate.
-sc_tests_makefile_variable_order: sc_ensure_testsuite_has_run
-	@for file in `find tests -name Makefile.in -print`; do \
-	  latevars=`sed -n \
-	    -e :x -e 's/#.*//' \
-	    -e '/\\\\$$/{' -e N -e 'b x' -e '}' \
-## Literal TAB.
-	    -e '1,/^	/d' \
-## Allow @ so we match conditionals.
-	    -e '/^ *[a-zA-Z_@]\{1,\} *=/p' $$file`; \
-	  if test -n "$$latevars"; then \
-	    echo 'Ensure variables are expanded before rules' >&2; \
-	    echo "Variables are expanded too late in $$file:" >&2; \
-	    echo "$$latevars" | sed 's/^/  /' >&2; \
-	    exit 1; \
-	  fi; \
-	done
-
-## Using `:' as a PATH separator is not portable.
-sc_tests_PATH_SEPARATOR:
-	@if grep -E '\bPATH=.*:.*' $(xtests) ; then \
-	  echo "Use \`\$$PATH_SEPARATOR', not \`:', in PATH definitions above." 1>&2; \
-	  exit 1; \
-	fi
-
-sc_mkdir_p:
-	@if grep 'mkdir_p' $(srcdir)/automake.in $(ams) $(xtests); then \
-	  echo 'Do not use mkdir_p in the above files, use MKDIR_P.' 1>&2; \
-	  exit 1; \
-	fi
-
-## Try to make sure all @...@ substitutions are covered by our
-## substitution rule.
-sc_perl_at_substs:
-	@if test `grep -E '^[^#]*@[A-Za-z_0-9]+@' aclocal | wc -l` -ne 0; then \
-	  echo "Unresolved @...@ substitution in aclocal" 1>&2; \
-	  exit 1; \
-	fi
-	@if test `grep -E '^[^#]*@[A-Za-z_0-9]+@' automake | wc -l` -ne 0; then \
-	  echo "Unresolved @...@ substitution in automake" 1>&2; \
-	  exit 1; \
-	fi
-
-sc_unquoted_DESTDIR:
-	@if grep -E "[^\'\"]\\\$$\(DESTDIR" $(ams); then \
-	  echo 'Suspicious unquoted DESTDIR uses.' 1>&2 ; \
-	  exit 1; \
-	fi
-
-sc_tabs_in_texi:
-	@if grep '	' $(srcdir)/doc/automake.texi; then \
-	  echo 'Do not use tabs in the manual.' 1>&2; \
-	  exit 1; \
-	fi
-
-sc_at_in_texi:
-	@if grep -E '([^@]|^)@([	 ][^@]|$$)' $(srcdir)/doc/automake.texi; \
-	then \
-	  echo 'Unescaped @.' 1>&2; \
-	  exit 1; \
-	fi
-
-
 git-dist: maintainer-check
 ## Make sure the NEWS file is up-to-date.
 	@if sed 1q $(srcdir)/NEWS | grep -e "$(VERSION)" > /dev/null; then :; else \
diff --git a/configure.ac b/configure.ac
index aea14ad8f..e461e1774 100644
--- a/configure.ac
+++ b/configure.ac
@@ -328,6 +328,7 @@ AC_CONFIG_FILES([
   m4/Makefile
   tests/Makefile
 ])
+AC_CONFIG_LINKS([GNUmakefile:GNUmakefile])
 AC_CONFIG_LINKS([tests/defs:tests/defs])
 AC_CONFIG_FILES([tests/aclocal-${APIVERSION}:tests/aclocal.in],
                 [chmod +x tests/aclocal-${APIVERSION}],
diff --git a/syntax-checks.mk b/syntax-checks.mk
new file mode 100644
index 000000000..038420263
--- /dev/null
+++ b/syntax-checks.mk
@@ -0,0 +1,588 @@
+# Maintainer checks for Automake.  Requires GNU make.
+
+# Copyright (C) 2012 Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# We also have to take into account VPATH builds (where some generated
+# tests might be in `$(builddir)' rather than in `$(srcdir)'), TAP-based
+# tests script (which have a `.tap' extension) and helper scripts used
+# by other test cases (which have a `.sh' extension).
+xtests = \
+  `if test $(srcdir) = .; then \
+     dirs=.; \
+   else \
+     dirs='$(srcdir) .'; \
+   fi; \
+   for d in $$dirs; do \
+     for s in test tap sh; do \
+       ls $$d/tests/*.$$s 2>/dev/null; \
+     done; \
+   done | sort`
+
+ams = `find $(srcdir) -name '*.am'`
+
+# Some simple checks, and then ordinary check.  These are only really
+# guaranteed to work on my machine.
+syntax_check_rules = \
+sc_test_names \
+sc_diff_automake_in_automake \
+sc_diff_aclocal_in_automake \
+sc_perl_syntax \
+sc_no_brace_variable_expansions \
+sc_rm_minus_f \
+sc_no_for_variable_in_macro \
+sc_mkinstalldirs \
+sc_pre_normal_post_install_uninstall \
+sc_perl_no_undef \
+sc_perl_no_split_regex_space \
+sc_cd_in_backquotes \
+sc_cd_relative_dir \
+sc_perl_at_uscore_in_scalar_context \
+sc_perl_local_no_parens \
+sc_perl_local \
+sc_AMDEP_TRUE_in_automake_in \
+sc_tests_make_without_am_makeflags \
+sc_tests_obsolete_variables \
+sc_tests_plain_make \
+sc_tests_plain_autoconf \
+sc_tests_plain_autoupdate \
+sc_tests_plain_automake \
+sc_tests_plain_autom4te \
+sc_tests_plain_autoheader \
+sc_tests_plain_autoreconf \
+sc_tests_here_document_format \
+sc_tests_Exit_not_exit \
+sc_tests_automake_fails \
+sc_tests_plain_aclocal \
+sc_tests_plain_perl \
+sc_tests_required_after_defs \
+sc_tests_tap_plan \
+sc_tests_overriding_macros_on_cmdline \
+sc_tests_plain_sleep \
+sc_tests_plain_egrep_fgrep \
+sc_tests_PATH_SEPARATOR \
+sc_tests_logs_duplicate_prefixes \
+sc_tests_makefile_variable_order \
+sc_mkdir_p \
+sc_perl_at_substs \
+sc_unquoted_DESTDIR \
+sc_tabs_in_texi \
+sc_at_in_texi
+
+$(syntax_check_rules): automake aclocal
+maintainer-check: $(syntax_check_rules)
+.PHONY: maintainer-check $(syntax_check_rules)
+
+## Check that the list of tests given in the Makefile is equal to the
+## list of all test scripts in the Automake testsuite.
+.PHONY: maintainer-check-list-of-tests
+maintainer-check-list-of-tests:
+	$(am__cd) tests && $(MAKE) $(AM_MAKEFLAGS) $@
+maintainer-check: maintainer-check-list-of-tests
+
+## Look for test whose names can cause spurious failures when used as
+## first argument to AC_INIT (chiefly because they might contain an
+## m4/m4sugar builtin or macro name).
+m4_builtins = \
+  __gnu__ \
+  __unix__ \
+  bpatsubst \
+  bregexp \
+  builtin \
+  changecom \
+  changequote \
+  changeword \
+  debugfile \
+  debugmode \
+  decr \
+  define \
+  defn \
+  divert \
+  divnum \
+  dnl \
+  dumpdef \
+  errprint \
+  esyscmd \
+  eval \
+  format \
+  ifdef \
+  ifelse \
+  include \
+  incr \
+  index \
+  indir \
+  len \
+  m4exit \
+  m4wrap \
+  maketemp \
+  mkstemp \
+  patsubst \
+  popdef \
+  pushdef \
+  regexp \
+  shift \
+  sinclude \
+  substr \
+  symbols \
+  syscmd \
+  sysval \
+  traceoff \
+  traceon \
+  translit \
+  undefine \
+  undivert
+sc_test_names:
+	@m4_builtin_rx=`echo $(m4_builtins) | sed 's/ /|/g'`; \
+	 m4_macro_rx="\\<($$m4_builtin_rx)\\>|\\<_?(A[CUMHS]|m4)_"; \
+	 if { \
+	   for t in $(xtests); do echo $$t; done \
+	     | LC_ALL=C grep -E "$$m4_macro_rx"; \
+	 }; then \
+	   echo "the names of the tests above can be problematic" 1>&2; \
+	   echo "Avoid test names that contain names of m4 macros" 1>&2; \
+	   exit 1; \
+	 fi
+
+## These check avoids accidental configure substitutions in the source.
+## There are exactly 9 lines that should be modified from automake.in to
+## automake, and 10 lines that should be modified from aclocal.in to
+## aclocal; these wors out to 32 and 34 lines of diffs, respectively.
+sc_diff_automake_in_automake:
+	@if test `diff $(srcdir)/automake.in automake | wc -l` -ne 32; then \
+	  echo "found too many diffs between automake.in and automake" 1>&2; \
+	  diff -c $(srcdir)/automake.in automake; \
+	  exit 1; \
+	fi
+sc_diff_aclocal_in_aclocal:
+	@if test `diff $(srcdir)/aclocal.in aclocal | wc -l` -ne 34; then \
+	  echo "found too many diffs between aclocal.in and aclocal" 1>&2; \
+	  diff -c $(srcdir)/aclocal.in aclocal; \
+	  exit 1; \
+	fi
+
+## Syntax check with default Perl (on my machine, Perl 5).
+sc_perl_syntax:
+	@perllibdir="./lib$(PATH_SEPARATOR)$(srcdir)/lib" $(PERL) -c -w automake
+	@perllibdir="./lib$(PATH_SEPARATOR)$(srcdir)/lib" $(PERL) -c -w aclocal
+
+## expect no instances of '${...}'.  However, $${...} is ok, since that
+## is a shell construct, not a Makefile construct.
+sc_no_brace_variable_expansions:
+	@if grep -F '$${' $(ams) | grep -F -v '$$$$'; then \
+	  echo "Found too many uses of '\$${' in the lines above." 1>&2; \
+	  exit 1;				\
+	else :; fi
+
+## Make sure `rm' is called with `-f'.
+sc_rm_minus_f:
+	@if grep -v '^#' $(ams) $(xtests) \
+	   | grep -E '\<rm ([^-]|\-[^f ]*\>)'; \
+	then \
+	  echo "Suspicious 'rm' invocation." 1>&2; \
+	  exit 1;				\
+	else :; fi
+
+## Never use something like `for file in $(FILES)', this doesn't work
+## if FILES is empty or if it contains shell meta characters (e.g. $ is
+## commonly used in Java filenames).
+sc_no_for_variable_in_macro:
+	@if grep 'for .* in \$$(' $(ams); then \
+	  echo 'Use "list=$$(mumble); for var in $$$$list".' 1>&2 ; \
+	  exit 1; \
+	else :; fi
+
+## Make sure all invocations of mkinstalldirs are correct.
+sc_mkinstalldirs:
+	@if grep -n 'mkinstalldirs' $(ams) | \
+	      grep -F -v '$$(mkinstalldirs)'; then \
+	  echo "Found incorrect use of mkinstalldirs in the lines above" 1>&2; \
+	  exit 1; \
+	else :; fi
+
+## Make sure all calls to PRE/NORMAL/POST_INSTALL/UNINSTALL
+sc_pre_normal_post_install_uninstall:
+	@if grep -E -n '\((PRE|NORMAL|POST)_(|UN)INSTALL\)' $(ams) | \
+	      grep -v ':##' | grep -v ':	@\$$('; then \
+	  echo "Found incorrect use of PRE/NORMAL/POST_INSTALL/UNINSTALL in the lines above" 1>&2; \
+	  exit 1; \
+	else :; fi
+
+## We never want to use "undef", only "delete", but for $/.
+sc_perl_no_undef:
+	@if grep -n -w 'undef ' $(srcdir)/automake.in | \
+	      grep -F -v 'undef $$/'; then \
+	  echo "Found undef in automake.in; use delete instead" 1>&2; \
+	  exit 1; \
+	fi
+
+## We never want split (/ /,...), only split (' ', ...).
+sc_perl_no_split_regex_space:
+	@if grep -n 'split (/ /' $(srcdir)/automake.in; then \
+	  echo "Found bad split in the lines above." 1>&2; \
+	  exit 1; \
+	fi
+
+## Look for cd within backquotes
+sc_cd_in_backquotes:
+	@if grep -n '^[^#]*` *cd ' $(srcdir)/automake.in $(ams); then \
+	  echo "Consider using \$$(am__cd) in the lines above." 1>&2; \
+	  exit 1; \
+	fi
+
+## Look for cd to a relative directory (may be influenced by CDPATH).
+## Skip some known directories that are OK.
+sc_cd_relative_dir:
+	@if grep -n '^[^#]*cd ' $(srcdir)/automake.in $(ams) | \
+	      grep -v 'echo.*cd ' | \
+	      grep -v 'am__cd =' | \
+	      grep -v '^[^#]*cd [./]' | \
+	      grep -v '^[^#]*cd \$$(top_builddir)' | \
+	      grep -v '^[^#]*cd "\$$\$$am__cwd' | \
+	      grep -v '^[^#]*cd \$$(abs' | \
+	      grep -v '^[^#]*cd "\$$(DESTDIR)'; then \
+	  echo "Consider using \$$(am__cd) in the lines above." 1>&2; \
+	  exit 1; \
+	fi
+
+## Using @_ in a scalar context is most probably a programming error.
+sc_perl_at_uscore_in_scalar_context:
+	@if grep -Hn '[^@_A-Za-z0-9][_A-Za-z0-9]*[^) ] *= *@_' $(srcdir)/automake.in; then \
+	  echo "Using @_ in a scalar context in the lines above." 1>&2; \
+	  exit 1; \
+	fi
+
+## Forbid using parens with `local' to ease counting.
+sc_perl_local_no_parens:
+	@if grep '^[ \t]*local *(' $(srcdir)/automake.in; then \
+	  echo "Don't use \`local' with parens: use several \`local' above." >&2; \
+	  exit 1; \
+	fi
+
+## Allow only few variables to be localized in Automake.
+sc_perl_local:
+	@if egrep -v '^[ \t]*local \$$[_~]( *=|;)' $(srcdir)/automake.in | \
+	        grep '^[ \t]*local [^*]'; then \
+	  echo "Please avoid \`local'." 1>&2; \
+	  exit 1; \
+	fi
+
+## Don't let AMDEP_TRUE substitution appear in automake.in.
+sc_AMDEP_TRUE_in_automake_in:
+	@if grep '@AMDEP''_TRUE@' $(srcdir)/automake.in; then \
+	  echo "Don't put AMDEP_TRUE substitution in automake.in" 1>&2; \
+	  exit 1; \
+	fi
+
+## Recursive make invocations should always pass $(AM_MAKEFLAGS)
+## to $(MAKE), for portability to non-GNU make.
+sc_tests_make_without_am_makeflags:
+	@if grep '^[^#].*(MAKE) ' $(ams) $(srcdir)/automake.in | \
+		grep -v 'AM_MAKEFLAGS'; then \
+	  echo 'Use $$(MAKE) $$(AM_MAKEFLAGS).' 1>&2; \
+	  exit 1; \
+	fi
+
+## Look out for some obsolete variables.
+sc_tests_obsolete_variables:
+	@vars=" \
+	  using_tap \
+	  parallel_tests \
+	  test_prefer_config_shell \
+	  original_AUTOMAKE \
+	  original_ACLOCAL \
+	"; \
+	seen=""; \
+	for v in $$vars; do \
+	  if grep -E "\b$$v\b" \
+	    $(xtests) $(srcdir)/tests/defs \
+	    $(srcdir)/tests/defs-static.in \
+	  ; then \
+	    seen="$$seen $$v"; \
+	  fi; \
+	done; \
+	if test -n "$$seen"; then \
+	  for v in $$seen; do \
+	    echo "Variable '$$v' is obsolete, use 'am_$$v' instead." 1>&2; \
+	  done; \
+	  exit 1; \
+	else :; fi
+
+## Tests should never call make directly.
+sc_tests_plain_make:
+	@if grep -v '^#' $(xtests) | $(EGREP) ':[ 	]*make( |$$)'; then \
+	  echo 'Do not run "make" in the above tests.  Use "$$MAKE" instead.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Tests should never call autoconf directly.
+sc_tests_plain_autoconf:
+	@if grep -v '^#' $(xtests) | grep ':[	]*autoconf\>'; then \
+	  echo 'Do not run "autoconf" in the above tests.  Use "$$AUTOCONF" instead.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Tests should never call autoupdate directly.
+sc_tests_plain_autoupdate:
+	@if grep -v '^#' $(xtests) | grep ':[	]*autoupdate\>'; then \
+	  echo 'Do not run "autoupdate" in the above tests.  Use "$$AUTOUPDATE" instead.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Tests should never call automake directly.
+sc_tests_plain_automake:
+	@if grep -v '^#' $(xtests) | grep -E ':[	]*automake\>([^:]|$$)'; then \
+	  echo 'Do not run "automake" in the above tests.  Use "$$AUTOMAKE" instead.' 1>&2;  \
+	  exit 1; \
+	fi
+
+## Tests should never call autoheader directly.
+sc_tests_plain_autoheader:
+	@if grep -v '^#' $(xtests) | grep ':[	]*autoheader\>'; then \
+	  echo 'Do not run "autoheader" in the above tests.  Use "$$AUTOHEADER" instead.' 1>&2;  \
+	  exit 1; \
+	fi
+
+## Tests should never call autoreconf directly.
+sc_tests_plain_autoreconf:
+	@if grep -v '^#' $(xtests) | grep ':[	]*autoreconf\>'; then \
+	  echo 'Do not run "autoreconf" in the above tests.  Use "$$AUTORECONF" instead.' 1>&2;  \
+	  exit 1; \
+	fi
+
+## Tests should never call autom4te directly.
+sc_tests_plain_autom4te:
+	@if grep -v '^#' $(xtests) | grep ':[	]*autom4te\>'; then \
+	  echo 'Do not run "autom4te" in the above tests.  Use "$$AUTOM4TE" instead.' 1>&2;  \
+	  exit 1; \
+	fi
+
+## Tests should only use END and EOF for here documents
+## (so that the next test is effective).
+sc_tests_here_document_format:
+	@if grep '<<' $(xtests) | grep -v 'END' | grep -v 'EOF'; then \
+	  echo 'Use here documents with "END" and "EOF" only, for greppability.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Tests should never call exit directly, but use Exit.
+## This is so that the exit status is transported correctly across the 0 trap.
+## Ignore comments, testsuite self tests, and one perl line in ext2.test.
+sc_tests_Exit_not_exit:
+	@found=false; for file in $(xtests); do \
+	  case $$file in */self-check-*) continue;; esac; \
+	  res=`sed -n -e '/^#/d; /^\$$PERL/d' -e '/<<.*END/,/^END/b' \
+		      -e '/<<.*EOF/,/^EOF/b' -e '/exit [$$0-9]/p' $$file`; \
+	  if test -n "$$res"; then \
+	    echo "$$file:$$res"; \
+	    found=true; \
+	  fi; \
+	done; \
+	if $$found; then \
+	  echo 'Do not call plain "exit", use "Exit" instead, in above tests.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Use AUTOMAKE_fails when appropriate
+sc_tests_automake_fails:
+	@if grep -v '^#' $(xtests) | grep '\$$AUTOMAKE.*&&.*[eE]xit'; then \
+	  echo 'Use AUTOMAKE_fails + grep to catch automake failures in the above tests.' 1>&2;  \
+	  exit 1; \
+	fi
+
+## Tests should never call aclocal directly.
+sc_tests_plain_aclocal:
+	@if grep -v '^#' $(xtests) | grep ':[	]*aclocal\>'; then \
+	  echo 'Do not run "aclocal" in the above tests.  Use "$$ACLOCAL" instead.' 1>&2;  \
+	  exit 1; \
+	fi
+
+## Tests should never call perl directly.
+sc_tests_plain_perl:
+	@if grep -v '^#' $(xtests) | grep ':[	]*perl\>'; then \
+	  echo 'Do not run "perl" in the above tests.  Use "$$PERL" instead.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Setting `required' after sourcing `./defs' is a bug.
+sc_tests_required_after_defs:
+	@for file in $(xtests); do \
+	  if out=`sed -n '/defs/,$${/required=/p;}' $$file`; test -n "$$out"; then \
+	    echo 'Do not set "required" after sourcing "defs" in '"$$file: $$out" 1>&2; \
+	    exit 1; \
+	  fi; \
+	done
+
+## TAP-based test scripts should not forget to declare a TAP plan.  In
+## case it is not known in advance how many tests will be run, a "lazy"
+## plan can be used; but its use should be deliberate, explicitly declared
+## with a "plan_ later" call, rather than the result of an oversight.
+## This check helps to ensure this is indeed the case.
+sc_tests_tap_plan:
+	@with_plan=`grep -l '^ *plan_ ' $(srcdir)/tests/*.tap`; \
+	 with_plan=`echo $$with_plan`; \
+	 ok=:; \
+	 for t in $(srcdir)/tests/*.tap; do \
+	   case " $$with_plan " in *" $$t "*) continue;; esac; \
+	   case $$t in \
+	     *-w.tap) \
+	       : it is ok for an *auto-generated* test sourcing an \
+	       : hand-written one not to declare a TAP plan: that will \
+	       : be done by the sourced test; \
+	       t2=`echo $$t | sed -e 's|.*/||' -e 's/-w\.tap$$/.tap/'` \
+	         && grep -E "^ *\\.  *[^ 	]*/$$t2\\b" $$t >/dev/null \
+	         && continue || : ;; \
+	   esac; \
+	   ok=false; echo $$t; \
+	 done; \
+	 $$ok || { \
+	  echo 'The tests above do not declare a TAP plan.' 1>&2; \
+	  exit 1; \
+	 }
+
+## Overriding a Makefile macro on the command line is not portable when
+## recursive targets are used.  Better use an envvar.  SHELL is an
+## exception, POSIX says it can't come from the environment.  V, DESTDIR,
+## DISTCHECK_CONFIGURE_FLAGS and DISABLE_HARD_ERRORS are exceptions, too,
+## as package authors are urged not to initialize them anywhere.
+sc_tests_overriding_macros_on_cmdline:
+	@if grep -E '\$$MAKE .*(SHELL=.*=|=.*SHELL=)' $(xtests); then \
+	  echo 'Rewrite "$$MAKE foo=bar SHELL=$$SHELL" as "foo=bar $$MAKE -e SHELL=$$SHELL"' 1>&2; \
+	  echo ' in the above lines, it is more portable.' 1>&2; \
+	  exit 1; \
+	fi
+# The first s/// tries to account for usages like "$MAKE || st=$?".
+# DISTCHECK_CONFIGURE_FLAGS is allowed to contain whitespace in its
+# definition, hence the more complex last three substitutions below.
+	@if sed -e 's/ || .*//' -e 's/ && .*//' \
+	        -e 's/ DESTDIR=[^ ]*/ /' -e 's/ SHELL=[^ ]*/ /' \
+	        -e 's/ V=[^ ]*/ /' -e 's/ DISABLE_HARD_ERRORS=[^ ]*/ /' \
+	        -e "s/ DISTCHECK_CONFIGURE_FLAGS='[^']*'/ /" \
+		-e 's/ DISTCHECK_CONFIGURE_FLAGS="[^"]*"/ /' \
+		-e 's/ DISTCHECK_CONFIGURE_FLAGS=[^ ]/ /' \
+	      $(xtests) | grep '\$$MAKE .*='; then \
+	  echo 'Rewrite "$$MAKE foo=bar" as "foo=bar $$MAKE -e" in the above lines,' 1>&2; \
+	  echo 'it is more portable.' 1>&2; \
+	  exit 1; \
+	fi
+	@if grep 'SHELL=.*\$$MAKE' $(xtests); then \
+	  echo '$$MAKE ignores the SHELL envvar, use "$$MAKE SHELL=$$SHELL" in' 1>&2; \
+	  echo 'the above lines.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Never use `sleep 1' to create files with different timestamps.
+## Use `$sleep' instead.  Some filesystems (e.g., Windows') have only
+## a 2sec resolution.
+sc_tests_plain_sleep:
+	@if grep -E '\bsleep +[12345]\b' $(xtests); then \
+	  echo 'Do not use "sleep x" in the above tests.  Use "$$sleep" instead.' 1>&2; \
+	  exit 1; \
+	fi
+
+## fgrep and egrep are not required by POSIX.
+sc_tests_plain_egrep_fgrep:
+	@if grep -E '\b[ef]grep\b' $(xtests) ; then \
+	  echo 'Do not use egrep or fgrep in test cases.  Use $$FGREP or $$EGREP.' 1>&2; \
+	  exit 1; \
+	fi
+	@if grep -E '\b[ef]grep\b' $(ams) $(srcdir)/m4/*.m4; then \
+	  echo 'Do not use egrep or fgrep in the above files, they are not portable.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Rule to ensure that the testsuite has been run before.  We don't depend on `check'
+## here, because that would be very wasteful in the common case.  We could run
+## `make check RECHECK_LOGS=' and avoid toplevel races with AM_RECURSIVE_TARGETS.
+## Suggest keeping test directories around for greppability of the Makefile.in files.
+sc_ensure_testsuite_has_run:
+	@if test ! -f tests/test-suite.log; then \
+	  echo "Run \`env keep_testdirs=yes make check' before \`maintainer-check'" >&2; \
+	  exit 1; \
+	fi
+.PHONY: sc_ensure_testsuite_has_run
+
+## Ensure our warning and error messages do not contain duplicate 'warning:' prefixes.
+## This test actually depends on the testsuite having been run before.
+sc_tests_logs_duplicate_prefixes: sc_ensure_testsuite_has_run
+	@if grep -E '(warning|error):.*(warning|error):' tests/*.log; then \
+	  echo 'Duplicate warning/error message prefixes seen in above tests.' >&2; \
+	  exit 1; \
+	fi
+
+## Ensure variables are listed before rules in Makefile.in files we generate.
+sc_tests_makefile_variable_order: sc_ensure_testsuite_has_run
+	@st=0; \
+	for file in `find tests -name Makefile.in -print`; do \
+	  latevars=`sed -n \
+	    -e :x -e 's/#.*//' \
+	    -e '/\\\\$$/{' -e N -e 'b x' -e '}' \
+	    -e '# Literal TAB.' \
+	    -e '1,/^	/d' \
+	    -e '# Allow @ so we match conditionals.' \
+	    -e '/^ *[a-zA-Z_@]\{1,\} *=/p' $$file`; \
+	  if test -n "$$latevars"; then \
+	    echo "Variables are expanded too late in $$file:" >&2; \
+	    echo "$$latevars" | sed 's/^/  /' >&2; \
+	    st=1; \
+	  fi; \
+	done; \
+	test $$st -eq 0 || { \
+	  echo 'Ensure variables are expanded before rules' >&2; \
+	  exit 1; \
+	}
+
+## Using `:' as a PATH separator is not portable.
+sc_tests_PATH_SEPARATOR:
+	@if grep -E '\bPATH=.*:.*' $(xtests) ; then \
+	  echo "Use \`\$$PATH_SEPARATOR', not \`:', in PATH definitions above." 1>&2; \
+	  exit 1; \
+	fi
+
+sc_mkdir_p:
+	@if grep 'mkdir_p' $(srcdir)/automake.in $(ams) $(xtests); then \
+	  echo 'Do not use mkdir_p in the above files, use MKDIR_P.' 1>&2; \
+	  exit 1; \
+	fi
+
+## Try to make sure all @...@ substitutions are covered by our
+## substitution rule.
+sc_perl_at_substs:
+	@if test `grep -E '^[^#]*@[A-Za-z_0-9]+@' aclocal | wc -l` -ne 0; then \
+	  echo "Unresolved @...@ substitution in aclocal" 1>&2; \
+	  exit 1; \
+	fi
+	@if test `grep -E '^[^#]*@[A-Za-z_0-9]+@' automake | wc -l` -ne 0; then \
+	  echo "Unresolved @...@ substitution in automake" 1>&2; \
+	  exit 1; \
+	fi
+
+sc_unquoted_DESTDIR:
+	@if grep -E "[^\'\"]\\\$$\(DESTDIR" $(ams); then \
+	  echo 'Suspicious unquoted DESTDIR uses.' 1>&2 ; \
+	  exit 1; \
+	fi
+
+sc_tabs_in_texi:
+	@if grep '	' $(srcdir)/doc/automake.texi; then \
+	  echo 'Do not use tabs in the manual.' 1>&2; \
+	  exit 1; \
+	fi
+
+sc_at_in_texi:
+	@if grep -E '([^@]|^)@([	 ][^@]|$$)' $(srcdir)/doc/automake.texi; \
+	then \
+	  echo 'Unescaped @.' 1>&2; \
+	  exit 1; \
+	fi