[PATCH] regex: remove glibc21.m4

[Paul Eggert]

It doesn’t seem to be needed any more; at least, I couldn’t
reproduce the circa-2013 problem.  Perhaps the recent
--conditional-dependencies fixes have removed the need for it.
* m4/glibc21.m4: Remove.  All uses removed.
---
 ChangeLog     |  8 ++++++++
 m4/glibc21.m4 | 34 ----------------------------------
 m4/regex.m4   |  3 +--
 modules/regex |  3 +--
 4 files changed, 10 insertions(+), 38 deletions(-)
 delete mode 100644 m4/glibc21.m4

diff --git a/ChangeLog b/ChangeLog
index 3f0a51d0e..97966b427 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2020-12-27  Paul Eggert  <eggert@cs.ucla.edu>
+
+       regex: remove glibc21.m4
+       It doesn’t seem to be needed any more; at least, I couldn’t
+       reproduce the circa-2013 problem.  Perhaps the recent
+       --conditional-dependencies fixes have removed the need for it.
+       * m4/glibc21.m4: Remove.  All uses removed.
+
 2020-12-26  Bruno Haible  <bruno@clisp.org>
 
        gnulib-tool: Make --conditional-dependencies work with --with-tests.
diff --git a/m4/glibc21.m4 b/m4/glibc21.m4
deleted file mode 100644
index ece484b5a..000000000
--- a/m4/glibc21.m4
+++ /dev/null
@@ -1,34 +0,0 @@
-# glibc21.m4 serial 5
-dnl Copyright (C) 2000-2002, 2004, 2008, 2010-2020 Free Software Foundation,
-dnl Inc.
-dnl This file is free software; the Free Software Foundation
-dnl gives unlimited permission to copy and/or distribute it,
-dnl with or without modifications, as long as this notice is preserved.
-
-# Test for the GNU C Library, version 2.1 or newer, or uClibc.
-# From Bruno Haible.
-
-AC_DEFUN([gl_GLIBC21],
-  [
-    AC_CACHE_CHECK([whether we are using the GNU C Library >= 2.1 or uClibc],
-      [ac_cv_gnu_library_2_1],
-      [AC_EGREP_CPP([Lucky],
-        [
-#include <features.h>
-#ifdef __GNU_LIBRARY__
- #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1) || (__GLIBC__ > 2)
-  Lucky GNU user
- #endif
-#endif
-#ifdef __UCLIBC__
- Lucky user
-#endif
-        ],
-        [ac_cv_gnu_library_2_1=yes],
-        [ac_cv_gnu_library_2_1=no])
-      ]
-    )
-    AC_SUBST([GLIBC21])
-    GLIBC21="$ac_cv_gnu_library_2_1"
-  ]
-)
diff --git a/m4/regex.m4 b/m4/regex.m4
index e723f5912..effe100b3 100644
--- a/m4/regex.m4
+++ b/m4/regex.m4
@@ -1,4 +1,4 @@
-# serial 70
+# serial 71
 
 # Copyright (C) 1996-2001, 2003-2020 Free Software Foundation, Inc.
 #
@@ -354,7 +354,6 @@ AC_DEFUN([gl_PREREQ_REGEX],
   AC_REQUIRE([AC_C_RESTRICT])
   AC_REQUIRE([AC_TYPE_MBSTATE_T])
   AC_REQUIRE([gl_EEMALLOC])
-  AC_REQUIRE([gl_GLIBC21])
   AC_CHECK_HEADERS([libintl.h])
   AC_CHECK_FUNCS_ONCE([isblank iswctype])
   AC_CHECK_DECLS([isblank], [], [], [[#include <ctype.h>]])
diff --git a/modules/regex b/modules/regex
index b987840d8..570b0bd55 100644
--- a/modules/regex
+++ b/modules/regex
@@ -9,7 +9,6 @@ lib/regex_internal.h
 lib/regexec.c
 lib/regcomp.c
 m4/eealloc.m4
-m4/glibc21.m4
 m4/regex.m4
 m4/mbstate_t.m4
 
@@ -23,7 +22,7 @@ builtin-expect  [test $ac_use_included_regex = yes]
 intprops        [test $ac_use_included_regex = yes]
 langinfo        [test $ac_use_included_regex = yes]
 libc-config     [test $ac_use_included_regex = yes]
-lock      [test "$ac_cv_gnu_library_2_1:$ac_use_included_regex" = no:yes]
+lock            [test $ac_use_included_regex = yes]
 memcmp          [test $ac_use_included_regex = yes]
 memmove         [test $ac_use_included_regex = yes]
 mbrtowc         [test $ac_use_included_regex = yes]
-- 
2.29.2