claws-mail/m4/glibc21.m4

# glibc21.m4 serial 3
dnl Copyright (C) 2000-2002, 2004 Free Software Foundation, 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.
# From Bruno Haible.

AC_DEFUN([gl_GLIBC21],
  [
    AC_CACHE_CHECK(whether we are using the GNU C Library 2.1 or newer,
      ac_cv_gnu_library_2_1,
      [AC_EGREP_CPP([Lucky GNU user],
	[
#include <features.h>
#ifdef __GNU_LIBRARY__
 #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 1) || (__GLIBC__ > 2)
  Lucky GNU user
 #endif
#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"
  ]
)