1 files changed, 71 insertions, 20 deletions

diff --git a/gl/m4/strstr.m4 b/gl/m4/strstr.m4
index 779957a..c486bdb 100644
--- a/gl/m4/strstr.m4
+++ b/gl/m4/strstr.m4
@@ -1,5 +1,5 @@
-# strstr.m4 serial 7
-dnl Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
+# strstr.m4 serial 16
+dnl Copyright (C) 2008-2013 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.
@@ -11,7 +11,51 @@ AC_DEFUN([gl_FUNC_STRSTR_SIMPLE],
   AC_REQUIRE([gl_FUNC_MEMCHR])
   if test "$gl_cv_func_memchr_works" != yes; then
     REPLACE_STRSTR=1
-    AC_LIBOBJ([strstr])
+  else
+    dnl Detect http://sourceware.org/bugzilla/show_bug.cgi?id=12092.
+    AC_CACHE_CHECK([whether strstr works],
+      [gl_cv_func_strstr_works_always],
+      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
+#include <string.h> /* for strstr */
+#define P "_EF_BF_BD"
+#define HAYSTACK "F_BD_CE_BD" P P P P "_C3_88_20" P P P "_C3_A7_20" P
+#define NEEDLE P P P P P
+]], [[return !!strstr (HAYSTACK, NEEDLE);
+    ]])],
+        [gl_cv_func_strstr_works_always=yes],
+        [gl_cv_func_strstr_works_always=no],
+        [dnl glibc 2.12 and cygwin 1.7.7 have a known bug.  uClibc is not
+         dnl affected, since it uses different source code for strstr than
+         dnl glibc.
+         dnl Assume that it works on all other platforms, even if it is not
+         dnl linear.
+         AC_EGREP_CPP([Lucky user],
+           [
+#ifdef __GNU_LIBRARY__
+ #include <features.h>
+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
+     || defined __UCLIBC__
+  Lucky user
+ #endif
+#elif defined __CYGWIN__
+ #include <cygwin/version.h>
+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
+  Lucky user
+ #endif
+#else
+  Lucky user
+#endif
+           ],
+           [gl_cv_func_strstr_works_always="guessing yes"],
+           [gl_cv_func_strstr_works_always="guessing no"])
+        ])
+      ])
+    case "$gl_cv_func_strstr_works_always" in
+      *yes) ;;
+      *)
+        REPLACE_STRSTR=1
+        ;;
+    esac
   fi
 ]) # gl_FUNC_STRSTR_SIMPLE
 
@@ -24,16 +68,18 @@ AC_DEFUN([gl_FUNC_STRSTR],
       [gl_cv_func_strstr_linear],
       [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
 #include <signal.h> /* for signal */
-#include <string.h> /* for memmem */
+#include <string.h> /* for strstr */
 #include <stdlib.h> /* for malloc */
 #include <unistd.h> /* for alarm */
-]], [[size_t m = 1000000;
+static void quit (int sig) { exit (sig + 128); }
+]], [[
+    int result = 0;
+    size_t m = 1000000;
     char *haystack = (char *) malloc (2 * m + 2);
     char *needle = (char *) malloc (m + 2);
-    void *result = 0;
     /* Failure to compile this test due to missing alarm is okay,
        since all such platforms (mingw) also have quadratic strstr.  */
-    signal (SIGALRM, SIG_DFL);
+    signal (SIGALRM, quit);
     alarm (5);
     /* Check for quadratic performance.  */
     if (haystack && needle)
@@ -44,36 +90,41 @@ AC_DEFUN([gl_FUNC_STRSTR],
         memset (needle, 'A', m);
         needle[m] = 'B';
         needle[m + 1] = 0;
-        result = strstr (haystack, needle);
+        if (!strstr (haystack, needle))
+          result |= 1;
       }
-    return !result;]])],
+    return result;
+    ]])],
         [gl_cv_func_strstr_linear=yes], [gl_cv_func_strstr_linear=no],
-        [dnl Only glibc >= 2.9 and cygwin >= 1.7.0 are known to have a
-         dnl strstr that works in linear time.
+        [dnl Only glibc > 2.12 on processors without SSE 4.2 instructions and
+         dnl cygwin > 1.7.7 are known to have a bug-free strstr that works in
+         dnl linear time.
          AC_EGREP_CPP([Lucky user],
            [
 #include <features.h>
 #ifdef __GNU_LIBRARY__
- #if (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 9) || (__GLIBC__ > 2)
+ #if ((__GLIBC__ == 2 && __GLIBC_MINOR__ > 12) || (__GLIBC__ > 2)) \
+     && !(defined __i386__ || defined __x86_64__) \
+     && !defined __UCLIBC__
   Lucky user
  #endif
 #endif
 #ifdef __CYGWIN__
  #include <cygwin/version.h>
- #if CYGWIN_VERSION_DLL_MAJOR >= 1007
+ #if CYGWIN_VERSION_DLL_COMBINED > CYGWIN_VERSION_DLL_MAKE_COMBINED (1007, 7)
   Lucky user
  #endif
 #endif
            ],
-           [gl_cv_func_strstr_linear=yes],
+           [gl_cv_func_strstr_linear="guessing yes"],
            [gl_cv_func_strstr_linear="guessing no"])
         ])
       ])
-    if test "$gl_cv_func_strstr_linear" != yes; then
-      REPLACE_STRSTR=1
-    fi
-  fi
-  if test $REPLACE_STRSTR = 1; then
-    AC_LIBOBJ([strstr])
+    case "$gl_cv_func_strstr_linear" in
+      *yes) ;;
+      *)
+        REPLACE_STRSTR=1
+        ;;
+    esac
   fi
 ]) # gl_FUNC_STRSTR