[PATCH] grep: fix multibyte regex handling under macOS

[PATCH] grep: fix multibyte regex handling under macOS

[Diomidis Spinellis via GitGitGadget]

From: Diomidis Spinellis <dds@aueb.gr>

The 2013 commit 29de20504e9 fixed t0070-fundamental.sh under Darwin
(macOS) by adopting Git's regex library.  However, this library is
compiled with NO_MBSUPPORT, which causes git-grep to work incorrectly
on multibyte (e.g. UTF-8) files.  Current macOS versions pass
t0070-fundamental.sh with the native macOS regex library, which
also supports multibyte characters.

Adjust the Makefile to use the native regex library, and call
setlocale(3) to set CTYPE according to the user's preference.  The
setlocale(3) call is required on all platforms, but in platforms
supporting gettext(3), setlocale(3) is called as a side-effect of
initializing gettext(3).

To avoid running the new tests on platforms still using the
compatibility library, which is compiled without multibyte
support, store the corresponding NO_REGEX setting in the
GIT-BUILD-OPTIONS file.  This makes it available to the test
scripts.  In addition, adjust the test-tool regex command to
work with multibyte regexes to further test a platform's
support for them.

Signed-off-by: Diomidis Spinellis <dds@aueb.gr>
---
    grep: fix multibyte regex handling under macOS
    
    The 2013 commit 29de20504e9 fixed t0070-fundamental.sh under Darwin
    (macOS) by adopting Git's regex library. However, this library is
    compiled with NO_MBSUPPORT, which causes git-grep to work incorrectly on
    multibyte (e.g. UTF-8) files. Current macOS versions pass
    t0070-fundamental.sh with the native macOS regex library, which also
    supports multibyte characters.
    
    Adjust the Makefile to use the native regex library, and call
    setlocale(3) to set CTYPE according to the user's preference. The
    setlocale(3) call is required on all platforms, but in platforms
    supporting gettext(3), setlocale(3) is called as a side-effect of
    initializing gettext(3).
    
    To avoid running the new tests on platforms still using the
    compatibility library, which is compiled without multibyte support,
    store the corresponding NO_REGEX setting in the GIT-BUILD-OPTIONS file.
    This makes it available to the test scripts. In addition, adjust the
    test-tool regex command to work with multibyte regexes to further test a
    platform's support for them.
    
    Signed-off-by: Diomidis Spinellis dds@aueb.gr

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1313%2Fdspinellis%2Ffix-macos-mb-grep-v1
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1313/dspinellis/fix-macos-mb-grep-v1
Pull-Request: https://github.com/git/git/pull/1313

 Makefile                  |  2 +-
 grep.c                    |  6 +++++-
 t/helper/test-regex.c     |  2 ++
 t/t7818-grep-multibyte.sh | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 42 insertions(+), 2 deletions(-)
 create mode 100755 t/t7818-grep-multibyte.sh

diff --git a/Makefile b/Makefile
index 04d0fd1fe60..d1a98257150 100644
--- a/Makefile
+++ b/Makefile
@@ -1427,7 +1427,6 @@ ifeq ($(uname_S),Darwin)
 		APPLE_COMMON_CRYPTO = YesPlease
 		COMPAT_CFLAGS += -DAPPLE_COMMON_CRYPTO
 	endif
-	NO_REGEX = YesPlease
 	PTHREAD_LIBS =
 endif
 
@@ -2970,6 +2969,7 @@ GIT-BUILD-OPTIONS: FORCE
 	@echo NO_PERL=\''$(subst ','\'',$(subst ','\'',$(NO_PERL)))'\' >>$@+
 	@echo NO_PTHREADS=\''$(subst ','\'',$(subst ','\'',$(NO_PTHREADS)))'\' >>$@+
 	@echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@+
+	@echo NO_REGEX=\''$(subst ','\'',$(subst ','\'',$(NO_REGEX)))'\' >>$@+
 	@echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@+
 	@echo PAGER_ENV=\''$(subst ','\'',$(subst ','\'',$(PAGER_ENV)))'\' >>$@+
 	@echo DC_SHA1=\''$(subst ','\'',$(subst ','\'',$(DC_SHA1)))'\' >>$@+
diff --git a/grep.c b/grep.c
index 82eb7da1022..c31657c3da3 100644
--- a/grep.c
+++ b/grep.c
@@ -10,6 +10,8 @@
 #include "quote.h"
 #include "help.h"
 
+#include <locale.h>
+
 static int grep_source_load(struct grep_source *gs);
 static int grep_source_is_binary(struct grep_source *gs,
 				 struct index_state *istate);
@@ -707,8 +709,10 @@ static struct grep_expr *grep_splice_or(struct grep_expr *x, struct grep_expr *y
 void compile_grep_patterns(struct grep_opt *opt)
 {
 	struct grep_pat *p;
-	struct grep_expr *header_expr = prep_header_patterns(opt);
+	struct grep_expr *header_expr;
 
+	setlocale(LC_CTYPE, "");
+	header_expr = prep_header_patterns(opt);
 	for (p = opt->pattern_list; p; p = p->next) {
 		switch (p->token) {
 		case GREP_PATTERN: /* atom */
diff --git a/t/helper/test-regex.c b/t/helper/test-regex.c
index d6f28ca8d14..ae4d7854abd 100644
--- a/t/helper/test-regex.c
+++ b/t/helper/test-regex.c
@@ -1,5 +1,6 @@
 #include "test-tool.h"
 #include "gettext.h"
+#include <locale.h>
 
 struct reg_flag {
 	const char *name;
@@ -85,6 +86,7 @@ int cmd__regex(int argc, const char **argv)
 	}
 	git_setup_gettext();
 
+	setlocale(LC_CTYPE, "");
 	ret = regcomp(&r, pat, flags);
 	if (ret) {
 		if (silent)
diff --git a/t/t7818-grep-multibyte.sh b/t/t7818-grep-multibyte.sh
new file mode 100755
index 00000000000..72129880fac
--- /dev/null
+++ b/t/t7818-grep-multibyte.sh
@@ -0,0 +1,34 @@
+#!/bin/sh
+
+test_description='grep multibyte characters'
+
+. ./test-lib.sh
+
+# Multibyte regex search is only supported with a native regex library
+# that supports them.
+# (The included library is compiled with NO_MBSUPPORT) and only if it
+test -z "$NO_REGEX" &&
+  LC_ALL=en_US.UTF-8 test-tool regex '^.$' '¿' &&
+  test_set_prereq MB_REGEX
+
+if ! test_have_prereq MB_REGEX
+then
+  skip_all='multibyte grep tests; Git compiled with NO_REGEX, NO_MBSUPPORT'
+  test_done
+fi
+
+test_expect_success 'setup' '
+	test_write_lines "¿" >file &&
+	git add file &&
+	LC_ALL="en_US.UTF-8" &&
+	export LC_ALL
+'
+test_expect_success 'grep exactly one char in single-char multibyte file' '
+	git grep "^.$"
+'
+
+test_expect_code 1 'grep two chars in single-char multibyte file' '
+	git grep ".."
+'
+
+test_done

base-commit: ad60dddad72dfb8367bd695028b5b8dc6c33661b
-- 
gitgitgadget

Re: [PATCH] grep: fix multibyte regex handling under macOS

[Eric Sunshine]

On Tue, Aug 23, 2022 at 4:04 PM Diomidis Spinellis via GitGitGadget
<gitgitgadget@gmail.com> wrote:
> diff --git a/t/t7818-grep-multibyte.sh b/t/t7818-grep-multibyte.sh
> +# Multibyte regex search is only supported with a native regex library
> +# that supports them.
> +# (The included library is compiled with NO_MBSUPPORT) and only if it
> +test -z "$NO_REGEX" &&

The comment above seems incomplete (i.e. "and only if it...").

Re: [PATCH] grep: fix multibyte regex handling under macOS

[Diomidis Spinellis]

On 23-Aug-22 23:40, Eric Sunshine wrote:
> On Tue, Aug 23, 2022 at 4:04 PM Diomidis Spinellis via GitGitGadget
> <gitgitgadget@gmail.com> wrote:
>> diff --git a/t/t7818-grep-multibyte.sh b/t/t7818-grep-multibyte.sh
>> +# Multibyte regex search is only supported with a native regex library
>> +# that supports them.
>> +# (The included library is compiled with NO_MBSUPPORT) and only if it
>> +test -z "$NO_REGEX" &&
> 
> The comment above seems incomplete (i.e. "and only if it...").

Thank you for pointing this out. I posted an update that fixes this.

Diomidis

[PATCH v2] grep: fix multibyte regex handling under macOS

[Diomidis Spinellis via GitGitGadget]

From: Diomidis Spinellis <dds@aueb.gr>

The 2013 commit 29de20504e9 fixed t0070-fundamental.sh under Darwin
(macOS) by adopting Git's regex library.  However, this library is
compiled with NO_MBSUPPORT, which causes git-grep to work incorrectly
on multibyte (e.g. UTF-8) files.  Current macOS versions pass
t0070-fundamental.sh with the native macOS regex library, which
also supports multibyte characters.

Adjust the Makefile to use the native regex library, and call
setlocale(3) to set CTYPE according to the user's preference.  The
setlocale(3) call is required on all platforms, but in platforms
supporting gettext(3), setlocale(3) is called as a side-effect of
initializing gettext(3).

To avoid running the new tests on platforms still using the
compatibility library, which is compiled without multibyte
support, store the corresponding NO_REGEX setting in the
GIT-BUILD-OPTIONS file.  This makes it available to the test
scripts.  In addition, adjust the test-tool regex command to
work with multibyte regexes to further test a platform's
support for them.

Signed-off-by: Diomidis Spinellis <dds@aueb.gr>
---
    grep: fix multibyte regex handling under macOS
    
    The 2013 commit 29de20504e9 fixed t0070-fundamental.sh under Darwin
    (macOS) by adopting Git's regex library. However, this library is
    compiled with NO_MBSUPPORT, which causes git-grep to work incorrectly on
    multibyte (e.g. UTF-8) files. Current macOS versions pass
    t0070-fundamental.sh with the native macOS regex library, which also
    supports multibyte characters.
    
    Adjust the Makefile to use the native regex library, and call
    setlocale(3) to set CTYPE according to the user's preference. The
    setlocale(3) call is required on all platforms, but in platforms
    supporting gettext(3), setlocale(3) is called as a side-effect of
    initializing gettext(3).
    
    To avoid running the new tests on platforms still using the
    compatibility library, which is compiled without multibyte support,
    store the corresponding NO_REGEX setting in the GIT-BUILD-OPTIONS file.
    This makes it available to the test scripts. In addition, adjust the
    test-tool regex command to work with multibyte regexes to further test a
    platform's support for them.
    
    Signed-off-by: Diomidis Spinellis dds@aueb.gr

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-git-1313%2Fdspinellis%2Ffix-macos-mb-grep-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-git-1313/dspinellis/fix-macos-mb-grep-v2
Pull-Request: https://github.com/git/git/pull/1313

Range-diff vs v1:

 1:  d29b93537f4 ! 1:  1d390b493c1 grep: fix multibyte regex handling under macOS
     @@ t/t7818-grep-multibyte.sh (new)
      +. ./test-lib.sh
      +
      +# Multibyte regex search is only supported with a native regex library
     -+# that supports them.
     -+# (The included library is compiled with NO_MBSUPPORT) and only if it
     ++# that supports it.
     ++# (The supplied compatibility library is compiled with NO_MBSUPPORT.)
      +test -z "$NO_REGEX" &&
      +  LC_ALL=en_US.UTF-8 test-tool regex '^.$' '¿' &&
      +  test_set_prereq MB_REGEX


 Makefile                  |  2 +-
 grep.c                    |  6 +++++-
 t/helper/test-regex.c     |  2 ++
 t/t7818-grep-multibyte.sh | 34 ++++++++++++++++++++++++++++++++++
 4 files changed, 42 insertions(+), 2 deletions(-)
 create mode 100755 t/t7818-grep-multibyte.sh

diff --git a/Makefile b/Makefile
index 04d0fd1fe60..d1a98257150 100644
--- a/Makefile
+++ b/Makefile
@@ -1427,7 +1427,6 @@ ifeq ($(uname_S),Darwin)
 		APPLE_COMMON_CRYPTO = YesPlease
 		COMPAT_CFLAGS += -DAPPLE_COMMON_CRYPTO
 	endif
-	NO_REGEX = YesPlease
 	PTHREAD_LIBS =
 endif
 
@@ -2970,6 +2969,7 @@ GIT-BUILD-OPTIONS: FORCE
 	@echo NO_PERL=\''$(subst ','\'',$(subst ','\'',$(NO_PERL)))'\' >>$@+
 	@echo NO_PTHREADS=\''$(subst ','\'',$(subst ','\'',$(NO_PTHREADS)))'\' >>$@+
 	@echo NO_PYTHON=\''$(subst ','\'',$(subst ','\'',$(NO_PYTHON)))'\' >>$@+
+	@echo NO_REGEX=\''$(subst ','\'',$(subst ','\'',$(NO_REGEX)))'\' >>$@+
 	@echo NO_UNIX_SOCKETS=\''$(subst ','\'',$(subst ','\'',$(NO_UNIX_SOCKETS)))'\' >>$@+
 	@echo PAGER_ENV=\''$(subst ','\'',$(subst ','\'',$(PAGER_ENV)))'\' >>$@+
 	@echo DC_SHA1=\''$(subst ','\'',$(subst ','\'',$(DC_SHA1)))'\' >>$@+
diff --git a/grep.c b/grep.c
index 82eb7da1022..c31657c3da3 100644
--- a/grep.c
+++ b/grep.c
@@ -10,6 +10,8 @@
 #include "quote.h"
 #include "help.h"
 
+#include <locale.h>
+
 static int grep_source_load(struct grep_source *gs);
 static int grep_source_is_binary(struct grep_source *gs,
 				 struct index_state *istate);
@@ -707,8 +709,10 @@ static struct grep_expr *grep_splice_or(struct grep_expr *x, struct grep_expr *y
 void compile_grep_patterns(struct grep_opt *opt)
 {
 	struct grep_pat *p;
-	struct grep_expr *header_expr = prep_header_patterns(opt);
+	struct grep_expr *header_expr;
 
+	setlocale(LC_CTYPE, "");
+	header_expr = prep_header_patterns(opt);
 	for (p = opt->pattern_list; p; p = p->next) {
 		switch (p->token) {
 		case GREP_PATTERN: /* atom */
diff --git a/t/helper/test-regex.c b/t/helper/test-regex.c
index d6f28ca8d14..ae4d7854abd 100644
--- a/t/helper/test-regex.c
+++ b/t/helper/test-regex.c
@@ -1,5 +1,6 @@
 #include "test-tool.h"
 #include "gettext.h"
+#include <locale.h>
 
 struct reg_flag {
 	const char *name;
@@ -85,6 +86,7 @@ int cmd__regex(int argc, const char **argv)
 	}
 	git_setup_gettext();
 
+	setlocale(LC_CTYPE, "");
 	ret = regcomp(&r, pat, flags);
 	if (ret) {
 		if (silent)
diff --git a/t/t7818-grep-multibyte.sh b/t/t7818-grep-multibyte.sh
new file mode 100755
index 00000000000..6cffcb33e26
--- /dev/null
+++ b/t/t7818-grep-multibyte.sh
@@ -0,0 +1,34 @@
+#!/bin/sh
+
+test_description='grep multibyte characters'
+
+. ./test-lib.sh
+
+# Multibyte regex search is only supported with a native regex library
+# that supports it.
+# (The supplied compatibility library is compiled with NO_MBSUPPORT.)
+test -z "$NO_REGEX" &&
+  LC_ALL=en_US.UTF-8 test-tool regex '^.$' '¿' &&
+  test_set_prereq MB_REGEX
+
+if ! test_have_prereq MB_REGEX
+then
+  skip_all='multibyte grep tests; Git compiled with NO_REGEX, NO_MBSUPPORT'
+  test_done
+fi
+
+test_expect_success 'setup' '
+	test_write_lines "¿" >file &&
+	git add file &&
+	LC_ALL="en_US.UTF-8" &&
+	export LC_ALL
+'
+test_expect_success 'grep exactly one char in single-char multibyte file' '
+	git grep "^.$"
+'
+
+test_expect_code 1 'grep two chars in single-char multibyte file' '
+	git grep ".."
+'
+
+test_done

base-commit: ad60dddad72dfb8367bd695028b5b8dc6c33661b
-- 
gitgitgadget

Re: [PATCH v2] grep: fix multibyte regex handling under macOS

[Junio C Hamano]

"Diomidis Spinellis via GitGitGadget" <gitgitgadget@gmail.com>
writes:

> From: Diomidis Spinellis <dds@aueb.gr>
>
> The 2013 commit 29de20504e9 fixed t0070-fundamental.sh under Darwin
> (macOS) by adopting Git's regex library.  However, this library is
> compiled with NO_MBSUPPORT, which causes git-grep to work incorrectly
> on multibyte (e.g. UTF-8) files.  Current macOS versions pass
> t0070-fundamental.sh with the native macOS regex library, which
> also supports multibyte characters.

Very nice to see the last sentence in that paragraph.

> Signed-off-by: Diomidis Spinellis <dds@aueb.gr>
> ---

This part, from here ...

>     grep: fix multibyte regex handling under macOS
>     
>     The 2013 commit 29de20504e9 fixed t0070-fundamental.sh under Darwin
>     (macOS) by adopting Git's regex library. However, this library is
>     compiled with NO_MBSUPPORT, which causes git-grep to work incorrectly on
>     multibyte (e.g. UTF-8) files. Current macOS versions pass
>     t0070-fundamental.sh with the native macOS regex library, which also
>     supports multibyte characters.
>     
>     Adjust the Makefile to use the native regex library, and call
>     setlocale(3) to set CTYPE according to the user's preference. The
>     setlocale(3) call is required on all platforms, but in platforms
>     supporting gettext(3), setlocale(3) is called as a side-effect of
>     initializing gettext(3).
>     
>     To avoid running the new tests on platforms still using the
>     compatibility library, which is compiled without multibyte support,
>     store the corresponding NO_REGEX setting in the GIT-BUILD-OPTIONS file.
>     This makes it available to the test scripts. In addition, adjust the
>     test-tool regex command to work with multibyte regexes to further test a
>     platform's support for them.
>     
>     Signed-off-by: Diomidis Spinellis dds@aueb.gr

... up to here does not need a separate sign-off.  It is primarily
to describe what got changed between v1 and this version.  The
changes can be seen in range-diff, and in some cases what the
range-diff shows is sufficient to understand the difference, but it
is better to either (1) supply explanation in your own words, or (2)
omit almost duplicate description.

> diff --git a/Makefile b/Makefile
> index 04d0fd1fe60..d1a98257150 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1427,7 +1427,6 @@ ifeq ($(uname_S),Darwin)
>  		APPLE_COMMON_CRYPTO = YesPlease
>  		COMPAT_CFLAGS += -DAPPLE_COMMON_CRYPTO
>  	endif
> -	NO_REGEX = YesPlease
>  	PTHREAD_LIBS =
>  endif

I notice that this is the ONLY conditional section in our primary
Makefile that switches upon the value of $(uname_<anything>).  After
the dust settles, we should move this whole part to config.mak.uname
as an unrelated clean-up.

Alternatively, you can choose to do that (without losing NO_REGEX)
as a preliminary clean-up patch and then build this "recent Darwin
has usable regexp library" change on top of it.  I do not have a
preference either way, other than that we do not want to see that
done as part of this change "while we are at it".

> diff --git a/grep.c b/grep.c
> index 82eb7da1022..c31657c3da3 100644
> --- a/grep.c
> +++ b/grep.c
> @@ -10,6 +10,8 @@
>  #include "quote.h"
>  #include "help.h"
>  
> +#include <locale.h>

Don't ever include system headers in generic *.c files.  The system
headers on different platforms have subtle ordering restrictions
among include files and definitions of feature test macros, and all
those subtleties are supposed to be handled in one central place, in
the "git-compat-util.h" file.

A source file specific only to a particular platform is a different
matter; they can include system headers that exist or are needed
only on those systems directly.

So far, "grep.c" has been successfully used for everybody (except
Darwin), and if it needs touching, that means something is still
wrong with Darwin.

Is is because you are not using gettext()?  I thought our
gettext.[ch] did consider some folks/platforms do not use system
gettext() but perhaps its support for such build environment is
slightly lacking and does not make necessary setlocale() calls.

If that is why you are mucking with this file, the right place to
add changes like this is not here specific to grep.c, but to the
start-up sequence that happens before cmd_main() inside
common-main.c or somewhere around there, I think.  Let me summon the
author of 5e9637c6 (i18n: add infrastructure for translating Git
with gettext, 2011-11-18) by Cc'ing.

Re: [PATCH v2] grep: fix multibyte regex handling under macOS

[Diomidis Spinellis]

On 24-Aug-22 21:56, Junio C Hamano wrote:
> "Diomidis Spinellis via GitGitGadget" <gitgitgadget@gmail.com>
> writes:
> 
>> From: Diomidis Spinellis <dds@aueb.gr>
>>
>> The 2013 commit 29de20504e9 fixed t0070-fundamental.sh under Darwin
>> (macOS) by adopting Git's regex library.  However, this library is
>> compiled with NO_MBSUPPORT, which causes git-grep to work incorrectly
>> on multibyte (e.g. UTF-8) files.  Current macOS versions pass
>> t0070-fundamental.sh with the native macOS regex library, which
>> also supports multibyte characters.
> 
> Very nice to see the last sentence in that paragraph.
> 
>> Signed-off-by: Diomidis Spinellis <dds@aueb.gr>
>> ---
> 
> This part, from here ...

[...]

> ... up to here does not need a separate sign-off.  

Apologies for this.  I was led to believe that gitgitgadget would 
seamlessly interface between GitHub's pull request and the Git project's 
email workflow, but I don't see this happening.  Not sure if this is due 
to a fault in gitgitgadget or due to my misuse of it.  I think 
gitgitgadget expects users not to squash their subsequent commits.  In 
any case, I'm switching to git-send-mail, which provides more visibility 
and control of the process.

>> diff --git a/Makefile b/Makefile
>> index 04d0fd1fe60..d1a98257150 100644
>> --- a/Makefile
>> +++ b/Makefile
>> @@ -1427,7 +1427,6 @@ ifeq ($(uname_S),Darwin)
>>   		APPLE_COMMON_CRYPTO = YesPlease
>>   		COMPAT_CFLAGS += -DAPPLE_COMMON_CRYPTO
>>   	endif
>> -	NO_REGEX = YesPlease
>>   	PTHREAD_LIBS =
>>   endif
> 
> I notice that this is the ONLY conditional section in our primary
> Makefile that switches upon the value of $(uname_<anything>).  After
> the dust settles, we should move this whole part to config.mak.uname
> as an unrelated clean-up.
> 
> Alternatively, you can choose to do that (without losing NO_REGEX)
> as a preliminary clean-up patch and then build this "recent Darwin
> has usable regexp library" change on top of it.  I do not have a
> preference either way, other than that we do not want to see that
> done as part of this change "while we are at it".

I was also surprised to see a $(uname) conditional in the Makefile.  I 
prefer to finish the macOS grep UTF-8 bug fix before discussing related 
house cleaning.

>> diff --git a/grep.c b/grep.c
>> index 82eb7da1022..c31657c3da3 100644
>> --- a/grep.c
>> +++ b/grep.c
>> @@ -10,6 +10,8 @@
>>   #include "quote.h"
>>   #include "help.h"
>>   
>> +#include <locale.h>
> 
> Don't ever include system headers in generic *.c files.  The system
> headers on different platforms have subtle ordering restrictions
> among include files and definitions of feature test macros, and all
> those subtleties are supposed to be handled in one central place, in
> the "git-compat-util.h" file.
> 
> A source file specific only to a particular platform is a different
> matter; they can include system headers that exist or are needed
> only on those systems directly.
> 
> So far, "grep.c" has been successfully used for everybody (except
> Darwin), and if it needs touching, that means something is still
> wrong with Darwin.

Thank you for clarifying the division of responsibility among files.  I 
changed the fix accordingly.

> Is is because you are not using gettext()?  I thought our
> gettext.[ch] did consider some folks/platforms do not use system
> gettext() but perhaps its support for such build environment is
> slightly lacking and does not make necessary setlocale() calls.

I believe that grep was working by accident on other platforms, thanks 
to setlocale calls made in gettext.c.  I don't think grep should depend 
on the implementation of gettext.  Thankfully, according to test 
results, it turns out that we can now globally initialize the CTYPE 
locale, making its state available both to gettext.c and grep.c.