Patch from Mandriva, done by pcpa.

Rebased for 4.8.2 / tmb

Signed-off-by: Thomas Backlund <tmb@mageia.org>

 gcc/config/i386/biarch64.h |    9 +++++++++
 gcc/opts-common.c          |   29 +++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff -Nurp gcc-4.8-20130725/gcc/config/i386/biarch64.h gcc-4.8-20130725-linux32/gcc/config/i386/biarch64.h
--- gcc-4.8-20130725/gcc/config/i386/biarch64.h	2013-01-10 22:38:27.000000000 +0200
+++ gcc-4.8-20130725-linux32/gcc/config/i386/biarch64.h	2013-07-29 18:56:22.560690959 +0300
@@ -27,3 +27,12 @@ see the files COPYING3 and COPYING.RUNTI
 
 #define TARGET_64BIT_DEFAULT (OPTION_MASK_ISA_64BIT | OPTION_MASK_ABI_64)
 #define TARGET_BI_ARCH 1
+
+#if defined(__linux__)
+#ifndef inhibit_libc
+#include <sys/syscall.h>
+#include <sys/personality.h>
+#define TARGET_32BIT_PERSONALITY \
+		((syscall(SYS_personality, 0xffffffff) & PER_MASK) == PER_LINUX32)
+#endif
+#endif
diff -Nurp gcc-4.8-20130725/gcc/opts-common.c gcc-4.8-20130725-linux32/gcc/opts-common.c
--- gcc-4.8-20130725/gcc/opts-common.c	2013-03-05 08:01:13.000000000 +0200
+++ gcc-4.8-20130725-linux32/gcc/opts-common.c	2013-07-29 18:56:22.560690959 +0300
@@ -21,6 +21,7 @@ along with GCC; see the file COPYING3.
 #include "system.h"
 #include "intl.h"
 #include "coretypes.h"
+#include "tm.h"
 #include "opts.h"
 #include "flags.h"
 #include "diagnostic.h"
@@ -744,6 +745,10 @@ decode_cmdline_options_to_array (unsigne
   unsigned int n, i;
   struct cl_decoded_option *opt_array;
   unsigned int num_decoded_options;
+#ifdef TARGET_32BIT_PERSONALITY
+  bool arch_flag = false;
+  bool arch_32bit = TARGET_32BIT_PERSONALITY;
+#endif
 
   opt_array = XNEWVEC (struct cl_decoded_option, argc);
 
@@ -773,11 +778,35 @@ decode_cmdline_options_to_array (unsigne
 	  continue;
 	}
 
+#ifdef TARGET_32BIT_PERSONALITY
+	if (!arch_flag && arch_32bit
+	    && opt[1] == 'm' && ((opt[2] == '3' && opt[3] == '2')
+				|| (opt[2] == '6' && opt[3] == '4'))
+	    && opt[4] == '\0')
+	arch_flag = true;
+#endif
+
       n = decode_cmdline_option (argv + i, lang_mask,
 				 &opt_array[num_decoded_options]);
       num_decoded_options++;
     }
 
+#ifdef TARGET_32BIT_PERSONALITY
+	if (!arch_flag && arch_32bit)
+	{
+	const char **argvec = XNEWVEC (const char *, 2);
+
+	argvec[0] = "-m32";
+	argvec[1] = NULL;
+	if (++num_decoded_options > argc)
+		opt_array = XRESIZEVEC (struct cl_decoded_option,
+					opt_array, num_decoded_options);
+	(void)decode_cmdline_option (argvec, lang_mask,
+				    &opt_array[num_decoded_options - 1]);
+	free (argvec);
+	}
+#endif
+
   *decoded_options = opt_array;
   *decoded_options_count = num_decoded_options;
   prune_options (decoded_options, decoded_options_count);