Update Gnulib to the latest git version

[deliverable/binutils-gdb.git] / gnulib / import / m4 / memchr.m4

diff --git a/gnulib/import/m4/memchr.m4 b/gnulib/import/m4/memchr.m4
index 25d32f0ec99966f29cc0157bbf600c01fe640129..c12d20ac76a5ec4ba1a9135f677d65226408502a 100644 (file)
--- a/gnulib/import/m4/memchr.m4
+++ b/gnulib/import/m4/memchr.m4
@@ -1,11 +1,13 @@
-# memchr.m4 serial 12
-dnl Copyright (C) 2002-2004, 2009-2016 Free Software Foundation, Inc.
+# memchr.m4 serial 15
+dnl Copyright (C) 2002-2004, 2009-2019 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.
 
 AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
 [
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+
   dnl Check for prerequisites for memory fence checks.
   gl_FUNC_MMAP_ANON
   AC_CHECK_HEADERS_ONCE([sys/mman.h])
@@ -23,10 +25,12 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
   if test $HAVE_MEMCHR = 1; then
     # Detect platform-specific bugs in some versions of glibc:
     # memchr should not dereference anything with length 0
-    #   http://bugzilla.redhat.com/499689
+    #   https://bugzilla.redhat.com/show_bug.cgi?id=499689
     # memchr should not dereference overestimated length after a match
-    #   http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737
-    #   http://sourceware.org/bugzilla/show_bug.cgi?id=10162
+    #   https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=521737
+    #   https://sourceware.org/bugzilla/show_bug.cgi?id=10162
+    # memchr should cast the second argument to 'unsigned char'.
+    #   This bug exists in Android 4.3.
     # Assume that memchr works on platforms that lack mprotect.
     AC_CACHE_CHECK([whether memchr works], [gl_cv_func_memchr_works],
       [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
@@ -72,13 +76,33 @@ AC_DEFUN_ONCE([gl_FUNC_MEMCHR],
       if (memchr (fence - 1, 0, 3) != fence - 1)
         result |= 4;
     }
+  /* Test against bug on Android 4.3.  */
+  {
+    char input[3];
+    input[0] = 'a';
+    input[1] = 'b';
+    input[2] = 'c';
+    if (memchr (input, 0x789abc00 | 'b', 3) != input + 1)
+      result |= 8;
+  }
   return result;
-]])], [gl_cv_func_memchr_works=yes], [gl_cv_func_memchr_works=no],
-      [dnl Be pessimistic for now.
-       gl_cv_func_memchr_works="guessing no"])])
-    if test "$gl_cv_func_memchr_works" != yes; then
-      REPLACE_MEMCHR=1
-    fi
+]])],
+         [gl_cv_func_memchr_works=yes],
+         [gl_cv_func_memchr_works=no],
+         [case "$host_os" in
+                             # Guess no on Android.
+            linux*-android*) gl_cv_func_memchr_works="guessing no" ;;
+                             # Guess yes on native Windows.
+            mingw*)          gl_cv_func_memchr_works="guessing yes" ;;
+                             # If we don't know, obey --enable-cross-guesses.
+            *)               gl_cv_func_memchr_works="$gl_cross_guess_normal" ;;
+          esac
+         ])
+      ])
+    case "$gl_cv_func_memchr_works" in
+      *yes) ;;
+      *) REPLACE_MEMCHR=1 ;;
+    esac
   fi
 ])