[PATCH v3 2/2] maint.mk: Replace grep with $(GREP)

[Roman Bolshakov <r.bolshakov@yadro.com>]

A project that uses maint.mk can specify regular expressions that are
not supported in system grep. Autoconf can discover an alias for GNU
grep and set it in GREP but it takes no effect for maint.mk

The patch provides an ability to use GNU grep if it was discovered by
autoconf and by calling GNU grep we don't get the messages in syntax-check:
  prohibit_diagnostic_without_format
  grep: empty (sub)expression
  grep: empty (sub)expression
  grep: empty (sub)expression
  grep: empty (sub)expression
  grep: empty (sub)expression
  grep: empty (sub)expression

Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
---
 modules/maintainer-makefile |   1 +
 top/maint.mk                | 116 ++++++++++++++++++------------------
 2 files changed, 59 insertions(+), 58 deletions(-)

diff --git a/modules/maintainer-makefile b/modules/maintainer-makefile
index 39b51583c..13b8c546a 100644
--- a/modules/maintainer-makefile
+++ b/modules/maintainer-makefile
@@ -14,6 +14,7 @@ configure.ac:
 AC_CONFIG_COMMANDS_PRE([m4_ifdef([AH_HEADER],
   [AC_SUBST([CONFIG_INCLUDE], m4_defn([AH_HEADER]))])])
 AC_REQUIRE([AC_PROG_SED])
+AC_REQUIRE([AC_PROG_GREP])
 
 Makefile.am:
 EXTRA_DIST += $(top_srcdir)/maint.mk
diff --git a/top/maint.mk b/top/maint.mk
index 1152ad698..c981567ba 100644
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -46,7 +46,7 @@ member-check =								\
 # Do not save the original name or timestamp in the .tar.gz file.
 # Use --rsyncable if available.
 gzip_rsyncable := \
-  $(shell gzip --help 2>/dev/null|grep rsyncable >/dev/null \
+  $(shell gzip --help 2>/dev/null|$(GREP) rsyncable >/dev/null \
     && printf %s --rsyncable)
 GZIP_ENV = '--no-name --best $(gzip_rsyncable)'
 
@@ -83,9 +83,9 @@ _sc_excl = \
   $(or $(exclude_file_name_regexp--$@),^$$)
 VC_LIST_EXCEPT = \
   $(VC_LIST) | $(SED) 's|^$(_dot_escaped_srcdir)/||' \
-	| if test -f $(srcdir)/.x-$@; then grep -vEf $(srcdir)/.x-$@; \
-	  else grep -Ev -e "$${VC_LIST_EXCEPT_DEFAULT-ChangeLog}"; fi \
-	| grep -Ev -e '($(VC_LIST_ALWAYS_EXCLUDE_REGEX)|$(_sc_excl))' \
+	| if test -f $(srcdir)/.x-$@; then $(GREP) -vEf $(srcdir)/.x-$@; \
+	  else $(GREP) -Ev -e "$${VC_LIST_EXCEPT_DEFAULT-ChangeLog}"; fi \
+	| $(GREP) -Ev -e '($(VC_LIST_ALWAYS_EXCLUDE_REGEX)|$(_sc_excl))' \
 	$(_prepend_srcdir_prefix)
 
 ifeq ($(origin prev_version_file), undefined)
@@ -292,23 +292,23 @@ define _sc_search_regexp
 									\
    : Filter by file name;						\
    if test -n "$$in_files"; then					\
-     files=$$(find $(srcdir) | grep -E "$$in_files"			\
-              | grep -Ev '$(_sc_excl)');				\
+     files=$$(find $(srcdir) | $(GREP) -E "$$in_files"			\
+              | $(GREP) -Ev '$(_sc_excl)');				\
    else									\
      files=$$($(VC_LIST_EXCEPT));					\
      if test -n "$$in_vc_files"; then					\
-       files=$$(echo "$$files" | grep -E "$$in_vc_files");		\
+       files=$$(echo "$$files" | $(GREP) -E "$$in_vc_files");		\
      fi;								\
    fi;									\
 									\
    : Filter by content;							\
    test -n "$$files"							\
      && test -n "$$containing"						\
-     && { files=$$(echo "$$files" | xargs grep -l "$$containing"); }	\
+     && { files=$$(echo "$$files" | xargs $(GREP) -l "$$containing"); }	\
      || :;								\
    test -n "$$files"							\
      && test -n "$$non_containing"					\
-     && { files=$$(echo "$$files" | xargs grep -vl "$$non_containing"); } \
+     && { files=$$(echo "$$files" | xargs $(GREP) -vl "$$non_containing"); } \
      || :;								\
 									\
    : Check for the construct;						\
@@ -316,15 +316,15 @@ define _sc_search_regexp
      if test -n "$$prohibit"; then					\
        echo "$$files" /dev/null						\
          | xargs							\
-             grep $$with_grep_options $(_ignore_case) -nE "$$prohibit"	\
-         | grep -vE "$${exclude:-^$$}"					\
+             $(GREP) $$with_grep_options $(_ignore_case) -nE "$$prohibit" \
+         | $(GREP) -vE "$${exclude:-^$$}"				\
          && { msg="$$halt" $(_sc_say_and_exit) }			\
          || :;								\
      else								\
        echo "$$files"							\
          | xargs							\
-             grep $$with_grep_options $(_ignore_case) -LE "$$require"	\
-         | grep .							\
+             $(GREP) $$with_grep_options $(_ignore_case) -LE "$$require" \
+         | $(GREP) .							\
          && { msg="$$halt" $(_sc_say_and_exit) }			\
          || :;								\
      fi									\
@@ -334,7 +334,7 @@ endef
 
 sc_avoid_if_before_free:
 	@$(VC_LIST_EXCEPT)						\
-	  | grep -v useless-if-before-free				\
+	  | $(GREP) -v useless-if-before-free				\
 	  | xargs							\
 	      $(srcdir)/$(_build-aux)/useless-if-before-free		\
 	      $(useless_free_options)					\
@@ -414,8 +414,8 @@ sc_error_exit_success:
 # "WARNING:" should be fully upper-cased, or fully lower-cased
 sc_error_message_warn_fatal:
 	@$(VC_LIST_EXCEPT)						\
-	  | xargs grep -nEA2 '[^rp]error *\(' /dev/null			\
-	  | grep -E '"Warning|"Fatal|"fatal'				\
+	  | xargs $(GREP) -nEA2 '[^rp]error *\(' /dev/null		\
+	  | $(GREP) -E '"Warning|"Fatal|"fatal'				\
 	  && { echo '$(ME): use FATAL, WARNING or warning' 1>&2;	\
 	       exit 1; }						\
 	  || :
@@ -423,9 +423,9 @@ sc_error_message_warn_fatal:
 # Error messages should not start with a capital letter
 sc_error_message_uppercase:
 	@$(VC_LIST_EXCEPT)						\
-	  | xargs grep -nEA2 '[^rp]error *\(' /dev/null			\
-	  | grep -E '"[A-Z]'						\
-	  | grep -vE '"FATAL|"WARNING|"Java|"C#|PRIuMAX'		\
+	  | xargs $(GREP) -nEA2 '[^rp]error *\(' /dev/null		\
+	  | $(GREP) -E '"[A-Z]'						\
+	  | $(GREP) -vE '"FATAL|"WARNING|"Java|"C#|PRIuMAX'		\
 	  && { echo '$(ME): found capitalized error message' 1>&2;	\
 	       exit 1; }						\
 	  || :
@@ -433,8 +433,8 @@ sc_error_message_uppercase:
 # Error messages should not end with a period
 sc_error_message_period:
 	@$(VC_LIST_EXCEPT)						\
-	  | xargs grep -nEA2 '[^rp]error *\(' /dev/null			\
-	  | grep -E '[^."]\."'						\
+	  | xargs $(GREP) -nEA2 '[^rp]error *\(' /dev/null		\
+	  | $(GREP) -E '[^."]\."'					\
 	  && { echo '$(ME): found error message ending in period' 1>&2;	\
 	       exit 1; }						\
 	  || :
@@ -479,8 +479,8 @@ perl_config_h_first_ =							\
 # You must include <config.h> before including any other header file.
 # This can possibly be via a package-specific header, if given by cfg.mk.
 sc_require_config_h_first:
-	@if $(VC_LIST_EXCEPT) | grep '\.c$$' > /dev/null; then		\
-	  files=$$($(VC_LIST_EXCEPT) | grep '\.c$$') &&			\
+	@if $(VC_LIST_EXCEPT) | $(GREP) '\.c$$' > /dev/null; then	\
+	  files=$$($(VC_LIST_EXCEPT) | $(GREP) '\.c$$') &&		\
 	  perl -n $(perl_config_h_first_) $$files ||			\
 	    { echo '$(ME): the above files include some other header'	\
 		'before <config.h>' 1>&2; exit 1; } || :;		\
@@ -498,10 +498,10 @@ sc_prohibit_HAVE_MBRTOWC:
 define _sc_header_without_use
   dummy=; : so we do not need a semicolon before each use;		\
   h_esc=`echo '[<"]'"$$h"'[">]'|$(SED) 's/\./\\\\./g'`;			\
-  if $(VC_LIST_EXCEPT) | grep '\.c$$' > /dev/null; then			\
-    files=$$(grep -l '^# *include '"$$h_esc"				\
-	     $$($(VC_LIST_EXCEPT) | grep '\.c$$')) &&			\
-    grep -LE "$$re" $$files | grep . &&					\
+  if $(VC_LIST_EXCEPT) | $(GREP) '\.c$$' > /dev/null; then		\
+    files=$$($(GREP) -l '^# *include '"$$h_esc"				\
+	     $$($(VC_LIST_EXCEPT) | $(GREP) '\.c$$')) &&		\
+    $(GREP) -LE "$$re" $$files | $(GREP) . &&				\
       { echo "$(ME): the above files include $$h but don't use it"	\
 	1>&2; exit 1; } || :;						\
   else :;								\
@@ -755,9 +755,9 @@ Exit_base := $(notdir $(Exit_witness_file))
 sc_require_test_exit_idiom:
 	@if test -f $(srcdir)/$(Exit_witness_file); then		\
 	  die=0;							\
-	  for i in $$(grep -l -F 'srcdir/$(Exit_base)'			\
+	  for i in $$($(GREP) -l -F 'srcdir/$(Exit_base)'		\
 		$$($(VC_LIST) tests)); do				\
-	    tail -n1 $$i | grep '^Exit .' > /dev/null			\
+	    tail -n1 $$i | $(GREP) '^Exit .' > /dev/null		\
 	      && : || { die=1; echo $$i; }				\
 	  done;								\
 	  test $$die = 1 &&						\
@@ -862,12 +862,12 @@ endef
 # Don't define macros that we already get from gnulib header files.
 sc_prohibit_always-defined_macros:
 	@if test -d $(gnulib_dir); then					\
-	  case $$(echo all: | grep -l -f - Makefile) in Makefile);; *)	\
+	  case $$(echo all: | $(GREP) -l -f - Makefile) in Makefile);; *) \
 	    echo '$(ME): skipping $@: you lack GNU grep' 1>&2; exit 0;;	\
 	  esac;								\
 	  regex=`$(def_sym_regex)`; export regex;			\
 	  $(VC_LIST_EXCEPT)						\
-	    | xargs sh -c 'echo $$regex | grep -E -f - "$$@"'		\
+	    | xargs sh -c 'echo $$regex | $(GREP) -E -f - "$$@"'	\
 	   	       dummy /dev/null					\
 	    && { printf '$(ME): define the above'			\
 			' via some gnulib .h file\n' 1>&2;		\
@@ -878,7 +878,7 @@ sc_prohibit_always-defined_macros:
 
 # Prohibit checked in backup files.
 sc_prohibit_backup_files:
-	@$(VC_LIST) | grep '~$$' &&				\
+	@$(VC_LIST) | $(GREP) '~$$' &&					\
 	  { echo '$(ME): found version controlled backup file' 1>&2;	\
 	    exit 1; } || :
 
@@ -1001,8 +1001,8 @@ ignore_doubled_word_match_RE_ ?= ^$$
 sc_prohibit_doubled_word:
 	@$(VC_LIST_EXCEPT)						\
 	  | xargs perl -n -0777 $(prohibit_doubled_word_)		\
-	  | grep -vE '$(ignore_doubled_word_match_RE_)'			\
-	  | grep .							\
+	  | $(GREP) -vE '$(ignore_doubled_word_match_RE_)'		\
+	  | $(GREP) .							\
 	  && { echo '$(ME): doubled words' 1>&2; exit 1; }		\
 	  || :
 
@@ -1030,8 +1030,8 @@ ignore_undesirable_word_sequence_RE_ ?= ^$$
 sc_prohibit_undesirable_word_seq:
 	@$(VC_LIST_EXCEPT)						\
 	  | xargs perl -n -0777 $(prohibit_undesirable_word_seq_)	\
-	  | grep -vE '$(ignore_undesirable_word_sequence_RE_)'		\
-	  | grep .							\
+	  | $(GREP) -vE '$(ignore_undesirable_word_sequence_RE_)'	\
+	  | $(GREP) .							\
 	  && { echo '$(ME): undesirable word sequence' >&2; exit 1; }   \
 	  || :
 
@@ -1066,7 +1066,7 @@ sc_prohibit_test_double_equal:
 # when it contains "ICONV".
 sc_proper_name_utf8_requires_ICONV:
 	@progs=$$($(VC_LIST_EXCEPT)					\
-		    | xargs grep -l 'proper_name_utf8 ''("');		\
+		    | xargs $(GREP) -l 'proper_name_utf8 ''("');	\
 	if test "x$$progs" != x; then					\
 	  fail=0;							\
 	  for p in $$progs; do						\
@@ -1075,7 +1075,7 @@ sc_proper_name_utf8_requires_ICONV:
 	      -ne 'exit !(/^LDADD =(.+?[^\\]\n)/ms && $$1 =~ /ICONV/)'	\
 	      $$dir/Makefile.am && continue;				\
 	    base=$$(basename "$$p" .c);					\
-	    grep "$${base}_LDADD.*ICONV)" $$dir/Makefile.am > /dev/null	\
+	    $(GREP) "$${base}_LDADD.*ICONV)" $$dir/Makefile.am > /dev/null	\
 	      || { fail=1; echo 1>&2 "$(ME): $$p uses proper_name_utf8"; }; \
 	  done;								\
 	  test $$fail = 1 &&						\
@@ -1136,12 +1136,12 @@ sc_makefile_at_at_check:
           -e ' && !/(\w+)\s+=.*\@\1\@$$/'				\
           -e ''$(_makefile_at_at_check_exceptions)			\
 	  -e 'and (print "$$ARGV:$$.: $$_"), $$m=1; END {exit !$$m}'	\
-	    $$($(VC_LIST_EXCEPT) | grep -E '(^|/)(Makefile\.am|[^/]+\.mk)$$') \
+	    $$($(VC_LIST_EXCEPT) | $(GREP) -E '(^|/)(Makefile\.am|[^/]+\.mk)$$') \
 	  && { echo '$(ME): use $$(...), not @...@' 1>&2; exit 1; } || :
 
 news-check: NEWS
 	$(AM_V_GEN)if $(SED) -n $(news-check-lines-spec)p $<		\
-	    | grep -E $(news-check-regexp) >/dev/null; then		\
+	    | $(GREP) -E $(news-check-regexp) >/dev/null; then		\
 	  :;								\
 	else								\
 	  echo 'NEWS: $$(news-check-regexp) failed to match' 1>&2;	\
@@ -1186,11 +1186,11 @@ generated_files ?= $(srcdir)/lib/*.[ch]
 _gl_translatable_string_re ?= \b(N?_|gettext *)\([^)"]*("|$$)
 sc_po_check:
 	@if test -f $(po_file); then					\
-	  grep -E -v '^(#|$$)' $(po_file)				\
-	    | grep -v '^src/false\.c$$' | sort > $@-1;			\
+	  $(GREP) -E -v '^(#|$$)' $(po_file)				\
+	    | $(GREP) -v '^src/false\.c$$' | sort > $@-1;		\
 	  { $(VC_LIST_EXCEPT); echo $(generated_files); }		\
 	    | xargs perl $(perl_translatable_files_list_)		\
-	    | xargs grep -E -l '$(_gl_translatable_string_re)'		\
+	    | xargs $(GREP) -E -l '$(_gl_translatable_string_re)'	\
 	    | $(SED) 's|^$(_dot_escaped_srcdir)/||'			\
 	    | sort -u > $@-2;						\
 	  diff -u -L $(po_file) -L $(po_file) $@-1 $@-2			\
@@ -1256,17 +1256,17 @@ _hv_regex_weak ?= ^ *\. .*/init\.sh"
 _hv_regex_strong ?= ^ *\. "\$${srcdir=\.}/init\.sh"
 sc_cross_check_PATH_usage_in_tests:
 	@if test -f $(_hv_file); then					\
-	  grep -l 'VERSION mismatch' $(_hv_file) >/dev/null		\
+	  $(GREP) -l 'VERSION mismatch' $(_hv_file) >/dev/null		\
 	    || { echo "$@: skipped: no such file: $(_hv_file)" 1>&2;	\
 		 exit 0; };						\
-	  grep -lE '$(_hv_regex_strong)' $(_hv_file) >/dev/null		\
+	  $(GREP) -lE '$(_hv_regex_strong)' $(_hv_file) >/dev/null	\
 	    || { echo "$@: $(_hv_file) lacks conforming use of init.sh" 1>&2; \
 		 exit 1; };						\
-	  good=$$(grep -E '$(_hv_regex_strong)' $(_hv_file));		\
+	  good=$$($(GREP) -E '$(_hv_regex_strong)' $(_hv_file));	\
 	  $(VC_LIST_EXCEPT)						\
-	    | xargs grep -lE '$(_hv_regex_weak)'			\
-	    | xargs grep -LFx "$$good"					\
-	    | grep .							\
+	    | xargs $(GREP) -lE '$(_hv_regex_weak)'			\
+	    | xargs $(GREP) -LFx "$$good"				\
+	    | $(GREP) .							\
 	    && { printf "$(ME): the above files use"			\
 			" path_prepend_ inconsistently\n" 1>&2;		\
 		 exit 1; }						\
@@ -1463,7 +1463,7 @@ check: $(gl_public_submodule_commit)
 ALL_RECURSIVE_TARGETS += alpha beta stable
 alpha beta stable: $(local-check) writable-files $(submodule-checks)
 	$(AM_V_GEN)test $@ = stable					\
-	  && { echo $(VERSION) | grep -E '^[0-9]+(\.[0-9]+)+$$'		\
+	  && { echo $(VERSION) | $(GREP) -E '^[0-9]+(\.[0-9]+)+$$'	\
 	       || { echo "invalid version string: $(VERSION)" 1>&2; exit 1;};}\
 	  || :
 	$(AM_V_at)$(MAKE) vc-diff-check
@@ -1561,7 +1561,7 @@ refresh-gnulib-patches:
 	       -e 'END{defined $$d and print $$d}' bootstrap.conf);	\
 	  test -n "$$t" && gl=$$t;					\
 	fi;								\
-	for diff in $$(cd $$gl; git ls-files | grep '\.diff$$'); do	\
+	for diff in $$(cd $$gl; git ls-files | $(GREP) '\.diff$$'); do	\
 	  b=$$(printf %s "$$diff"|$(SED) 's/\.diff$$//');		\
 	  VERSION_CONTROL=none						\
 	    patch "$(gnulib_dir)/$$b" "$$gl/$$diff" || exit 1;		\
@@ -1604,7 +1604,7 @@ update-copyright-env ?=
 # in the file .x-update-copyright.
 .PHONY: update-copyright
 update-copyright:
-	$(AM_V_GEN)grep -l -w Copyright                                  \
+	$(AM_V_GEN)$(GREP) -l -w Copyright                               \
 	  $$(export VC_LIST_EXCEPT_DEFAULT=COPYING && $(VC_LIST_EXCEPT)) \
 	  | $(update-copyright-env) xargs $(srcdir)/$(_build-aux)/$@
 
@@ -1618,9 +1618,9 @@ _gl_TS_dir ?= src
 ALL_RECURSIVE_TARGETS += sc_tight_scope
 sc_tight_scope: tight-scope.mk
 	@fail=0;							\
-	if ! grep '^ *export _gl_TS_headers *=' $(srcdir)/cfg.mk	\
+	if ! $(GREP) '^ *export _gl_TS_headers *=' $(srcdir)/cfg.mk	\
 		> /dev/null						\
-	   && ! grep -w noinst_HEADERS $(srcdir)/$(_gl_TS_dir)/Makefile.am \
+	   && ! $(GREP) -w noinst_HEADERS $(srcdir)/$(_gl_TS_dir)/Makefile.am \
 		> /dev/null 2>&1; then					\
 	    echo '$(ME): skipping $@';					\
 	else								\
@@ -1692,12 +1692,12 @@ _gl_tight_scope: $(bin_PROGRAMS)
 	hdr=`for f in $(_gl_TS_headers); do				\
 	       test -f $$f && d= || d=$(srcdir)/; echo $$d$$f; done`;	\
 	( printf '%s\n' '__.*' $(_gl_TS_unmarked_extern_functions);	\
-	  grep -h -A1 '^extern .*[^;]$$' $$src				\
-	    | grep -vE '^(extern |--|#)' | $(SED) 's/ .*//; /^$$/d';	\
+	  $(GREP) -h -A1 '^extern .*[^;]$$' $$src			\
+	    | $(GREP) -vE '^(extern |--|#)' | $(SED) 's/ .*//; /^$$/d';	\
 	  perl -lne							\
 	     '$(_gl_TS_function_match) and print $$1' $$hdr;		\
 	) | sort -u | $(SED) "$$sed_wrap" > $$t;			\
-	nm -g $(_gl_TS_obj_files)|$(SED) -n 's/.* T //p'|grep -Ev -f $$t \
+	nm -g $(_gl_TS_obj_files)|$(SED) -n 's/.* T //p'|$(GREP) -Ev -f $$t \
 	  && { echo the above functions should have static scope >&2;	\
 	       exit 1; } || : ;						\
 	( printf '%s\n' '__.*' main $(_gl_TS_unmarked_extern_vars);	\
@@ -1705,7 +1705,7 @@ _gl_tight_scope: $(bin_PROGRAMS)
 		$$hdr $(_gl_TS_other_headers)				\
 	) | sort -u | $(SED) "$$sed_wrap" > $$t;			\
 	nm -g $(_gl_TS_obj_files) | $(SED) -n 's/.* [BCDGRS] //p'	\
-            | sort -u | grep -Ev -f $$t					\
+            | sort -u | $(GREP) -Ev -f $$t				\
 	  && { echo the above variables should have static scope >&2;	\
 	       exit 1; } || :
 # TS-end
-- 
2.17.2 (Apple Git-113)