--- gcc-4.6-20110415/gcc/config/i386/biarch64.h.orig	2011-04-24 05:41:14.296592400 -0300
+++ gcc-4.6-20110415/gcc/config/i386/biarch64.h	2011-04-24 05:41:32.776642363 -0300
@@ -27,3 +27,12 @@ see the files COPYING3 and COPYING.RUNTI
 
 #define TARGET_64BIT_DEFAULT OPTION_MASK_ISA_64BIT
 #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
--- gcc-4.6-20110415/gcc/opts-common.c.orig	2011-04-24 05:41:22.864615786 -0300
+++ gcc-4.6-20110415/gcc/opts-common.c	2011-04-24 05:41:59.006715082 -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"
@@ -678,6 +679,10 @@ decode_cmdline_options_to_array (unsigne
   struct cl_decoded_option *opt_array;
   unsigned int num_decoded_options;
   bool argv_copied = false;
+#ifdef TARGET_32BIT_PERSONALITY
+  bool arch_flag = false;
+  bool arch_32bit = TARGET_32BIT_PERSONALITY;
+#endif
 
   opt_array = XNEWVEC (struct cl_decoded_option, argc);
 
@@ -706,12 +711,34 @@ decode_cmdline_options_to_array (unsigne
 	  n = 1;
 	  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)
+    {
+      char **argvec = XNEWVEC (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
+
   if (argv_copied)
     free (argv);
   *decoded_options = opt_array;