Merge GDB 7.5.1

gdb/gnulib/import/m4/glibc21.m4

Index: gdb/gnulib/import/m4/glibc21.m4
diff --git a/gdb/gnulib/import/m4/glibc21.m4 b/gdb/gnulib/import/m4/glibc21.m4
new file mode 100644
index 0000000000000000000000000000000000000000..c938fb1a0c3ecf70a8ce142d7ca998b9624c2360
--- /dev/null
+++ b/gdb/gnulib/import/m4/glibc21.m4
@@ -0,0 +1,34 @@
+# glibc21.m4 serial 5
+dnl Copyright (C) 2000-2002, 2004, 2008, 2010-2012 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"
+  ]
+)