tests: skip tests upon buggy mbrtowc implementations

Sed tests purposefully use invalid non-utf8 multibyte sequences to
test sed's handling of invalid input/program.
Some implementations wrongly accept invalid sequences, causing false
alarms. Add a test program to detect such buggy implementations and skip
the tests if needed.
See discussion in:
http://lists.gnu.org/archive/html/sed-devel/2016-07/msg00005.html
http://lists.gnu.org/archive/html/sed-devel/2016-07/msg00000.html
http://lists.gnu.org/archive/html/sed-devel/2016-06/msg00031.html
http://lists.gnu.org/archive/html/sed-devel/2016-06/msg00014.html

* bootstrap.conf: Add gnulib's closeout module.
* m4/.gitignore, lib/.gitignore, po/POTFILES.in: Adjust after adding
closeout module.
* testsuite/Makefile.am (check_PROGRAMS): Add new program.
* testsuite/test-mbrtowc.c: New program.
* testsuite/init.cfg (require_valid_ja_eucjp_locale_)
(require_valid_ja_shiftjis_locale_): New functions. Call test-mbrtowc
with known invalid multibyte sequences to ensure implementation is not
buggy and rejects them; Skip test otherwise.
* testsuite/invalid-mb-seq-UMR.sh: Use require_valid_ja_eucjp_locale_.
* testsuite/mb-charclass-non-utf8.sh: Use require_valid_ja_shiftjis_locale_.

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/.gitignore b/lib/.gitignore
index 303403b..7e85de9 100644
--- a/lib/.gitignore
+++ b/lib/.gitignore
@@ -210,3 +210,9 @@ xstrndup.h
 /progname.h
 /ignore-value.h
 /alignof.h
+/close-stream.c
+/close-stream.h
+/closeout.c
+/closeout.h
+/fpending.c
+/fpending.h