Pacify -DGNULIB_POSIXCHECK.

* bootstrap.conf (gnulib_modules): Add all modules suggested by
-DGNULIB_POSIXCHECK.
* src/files.c (file_name_split)
* src/getargs.c (getargs)
* src/location.c (boundary_set_from_string)
* src/output.c (output_skeleton)
* src/parse-gram.y (prologue_declaration)
* src/scan-gram.l (handle_syncline)
* src/symtab.c (symbol_new): Use mbschr and mbsrchr instead of
strchr and strrchr.  In the cases of command-line options, file
names, and thus locations, functionality may be improved.  In the
case of symbol names, there should be no functional difference as
all characters are ASCII, so the intended benefit is just warning
suppression.
(cherry picked from commit d143e9c33f)

Conflicts:

	src/output.c
	src/parse-gram.c
	src/parse-gram.h

bootstrap.conf

@@ -17,13 +17,14 @@
 
 # gnulib modules used by this package.
 gnulib_modules='
-  announce-gen argmatch assert config-h c-strcase configmake dirname
-  error extensions fopen-safer gendocs getopt-gnu gettext
-  git-version-gen hash inttypes javacomp-script javaexec-script
-  maintainer-makefile malloc-gnu mbswidth obstack quote quotearg
-  realloc-posix spawn-pipe stdbool stpcpy strerror strtoul strverscmp unistd
-  unistd-safer unlocked-io update-copyright unsetenv verify warnings
-  xalloc xalloc-die xstrndup
+  announce-gen argmatch assert calloc-posix close config-h c-strcase
+  configmake dirname error extensions fopen-safer gendocs getopt-gnu
+  gettext git-version-gen hash inttypes isnan javacomp-script
+  javaexec-script ldexpl maintainer-makefile malloc-gnu mbschr mbsrchr
+  mbswidth obstack perror pipe-posix quote quotearg realloc-posix
+  spawn-pipe stdbool stpcpy strdup-posix strerror strtoul strverscmp
+  unistd unistd-safer unlocked-io update-copyright unsetenv verify
+  warnings xalloc xalloc-die xstrndup
 
   fprintf-posix printf-posix snprintf-posix sprintf-posix
   vsnprintf-posix vsprintf-posix