+ else
+ dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+ AC_CACHE_CHECK([whether memmem works],
+ [gl_cv_func_memmem_works_always],
+ [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h> /* for memmem */
+#define P "_EF_BF_BD"
+#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
+#define NEEDLE P P P P P
+]], [[return !!memmem (HAYSTACK, strlen (HAYSTACK), NEEDLE, strlen (NEEDLE));
+ ]])],
+ [gl_cv_func_memmem_works_always=yes],
+ [gl_cv_func_memmem_works_always=no],
+ [dnl glibc 2.12 and cygwin 1.7.7 have a known bug. Assume that it
+ dnl works on all other platforms, even if it is not linear.
+ AC_EGREP_CPP([Lucky user],
+ [
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if (__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)
+ Lucky user
+ #endif
+#elif defined __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_MAJOR >= 1007 && CYGWIN_VERSION_DLL_MINOR > 7
+ Lucky user
+ #endif
+#else
+ Lucky user
+#endif
+ ],
+ [gl_cv_func_memmem_works_always=yes],
+ [gl_cv_func_memmem_works_always="guessing no"])
+ ])
+ ])
+ if test "$gl_cv_func_memmem_works_always" != yes; then
+ REPLACE_MEMMEM=1
+ AC_LIBOBJ([memmem])
+ fi