[v3] libstdc++/51785

2012-03-01  Benjamin Kosnik  <bkoz@redhat.com>
            Ramana Radhakrishnan <ramana@gcc.gnu.org>

	PR libstdc++/51785
	* acinclude.m4 (GLIBCXX_CHECK_STDIO_PROTO): New.
	* configure.ac: Call it.
	* configure: Regenerate.
	* config.h.in: Same.
	* config/os/gnu-linux/os_defines.h: Conditionally undefine
	_GLIBCXX_HAVE_GETS.
	* include/c_global/cstdio: Conditionally declare deprecated gets.
	* include/c_std/cstdio: Same.

diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index fe37a91..56711c0 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -1809,6 +1809,35 @@  AC_DEFUN([GLIBCXX_CHECK_STDLIB_PROTO], [
 ])
 
 dnl
+dnl Check whether required C++ overloads are present in <stdio.h>.
+dnl
+AC_DEFUN([GLIBCXX_CHECK_STDIO_PROTO], [
+
+  AC_LANG_SAVE
+  AC_LANG_CPLUSPLUS
+
+  AC_MSG_CHECKING([for gets declaration])
+  AC_CACHE_VAL(glibcxx_cv_gets, [
+  AC_COMPILE_IFELSE([AC_LANG_SOURCE(
+	  [#include <stdio.h>
+	   namespace test 
+	   {
+              using ::gets;
+	   }
+	])],
+	[glibcxx_cv_gets=yes],
+	[glibcxx_cv_gets=no]
+      )])
+
+  if test $glibcxx_cv_gets = yes; then
+    AC_DEFINE(HAVE_GETS, 1, [Define if gets is available in <stdio.h>.])
+  fi
+  AC_MSG_RESULT($glibcxx_cv_gets)
+
+  AC_LANG_RESTORE
+])
+
+dnl
 dnl Check whether macros, etc are present for <system_error>
 dnl
 AC_DEFUN([GLIBCXX_CHECK_SYSTEM_ERROR], [
diff --git a/libstdc++-v3/config/os/gnu-linux/os_defines.h b/libstdc++-v3/config/os/gnu-linux/os_defines.h
index c788cb0..c4aa305 100644
--- a/libstdc++-v3/config/os/gnu-linux/os_defines.h
+++ b/libstdc++-v3/config/os/gnu-linux/os_defines.h
@@ -1,6 +1,6 @@ 
 // Specific definitions for GNU/Linux  -*- C++ -*-
 
-// Copyright (C) 2000, 2001, 2002, 2003, 2009, 2010
+// Copyright (C) 2000, 2001, 2002, 2003, 2009, 2010, 2012
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -39,4 +39,11 @@ 
 
 #include <features.h>
 
+// Provide a declaration for the possibly deprecated gets function, as
+// glibc 2.15 and later does not declare gets for ISO C11 when
+// __GNU_SOURCE is defined.
+#if __GLIBC_PREREQ(2,15) && defined(_GNU_SOURCE)
+# undef _GLIBCXX_HAVE_GETS
+#endif
+
 #endif
diff --git a/libstdc++-v3/configure.ac b/libstdc++-v3/configure.ac
index 49de141..f04563e 100644
--- a/libstdc++-v3/configure.ac
+++ b/libstdc++-v3/configure.ac
@@ -136,6 +136,7 @@  GLIBCXX_ENABLE_WERROR([yes])
 # Checks for operating systems support that doesn't require linking.
 GLIBCXX_CHECK_MATH_PROTO
 GLIBCXX_CHECK_STDLIB_PROTO
+GLIBCXX_CHECK_STDIO_PROTO
 GLIBCXX_CHECK_SYSTEM_ERROR
 
 # For the streamoff typedef.
diff --git a/libstdc++-v3/include/c_global/cstdio b/libstdc++-v3/include/c_global/cstdio
index 049704d..d11743a 100644
--- a/libstdc++-v3/include/c_global/cstdio
+++ b/libstdc++-v3/include/c_global/cstdio
@@ -1,7 +1,7 @@ 
 // -*- C++ -*- forwarding header.
 
 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
-// 2006, 2007, 2008, 2009, 2010
+// 2006, 2007, 2008, 2009, 2010, 2012
 // Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
@@ -46,6 +46,10 @@ 
 #ifndef _GLIBCXX_CSTDIO
 #define _GLIBCXX_CSTDIO 1
 
+#ifndef _GLIBCXX_HAVE_GETS
+extern "C" extern char* gets (char* __s) __attribute__((deprecated));
+#endif
+
 // Get rid of those macros defined in <stdio.h> in lieu of real functions.
 #undef clearerr
 #undef fclose
@@ -67,7 +71,6 @@ 
 #undef ftell
 #undef fwrite
 #undef getc
-#undef getchar
 #undef gets
 #undef perror
 #undef printf
diff --git a/libstdc++-v3/include/c_std/cstdio b/libstdc++-v3/include/c_std/cstdio
index 510f599..1588fc9 100644
--- a/libstdc++-v3/include/c_std/cstdio
+++ b/libstdc++-v3/include/c_std/cstdio
@@ -1,7 +1,7 @@ 
 // -*- C++ -*- forwarding header.
 
 // Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
-// 2009, 2010  Free Software Foundation, Inc.
+// 2009, 2010, 2012  Free Software Foundation, Inc.
 //
 // This file is part of the GNU ISO C++ Library.  This library is free
 // software; you can redistribute it and/or modify it under the
@@ -45,6 +45,10 @@ 
 #include <bits/c++config.h>
 #include <stdio.h>
 
+#ifndef _GLIBCXX_HAVE_GETS
+extern "C" extern char* gets (char* __s) __attribute__((deprecated));
+#endif
+
 // Get rid of those macros defined in <stdio.h> in lieu of real functions.
 #undef clearerr
 #undef fclose