http://gcc.gnu.org/ml/java-patches/2010-q1/msg00058.html

diff -up gcc-4.3.6/libffi/configure.ac.unwind gcc-4.3.6/libffi/configure.ac
--- gcc-4.3.6/libffi/configure.ac.unwind	2010-05-06 19:19:46.000000000 +0200
+++ gcc-4.3.6/libffi/configure.ac	2012-07-08 22:32:03.657151000 +0200
@@ -243,6 +243,21 @@ if test x$TARGET = xSPARC; then
     fi
 fi
 
+if test x$TARGET = xX86_64; then
+    AC_CACHE_CHECK([assembler supports unwind section type],
+       libffi_cv_as_x86_64_unwind_section_type, [
+       libffi_cv_as_x86_64_unwind_section_type=yes
+       echo '.section .eh_frame,"a",@unwind' > conftest.s
+       if $CC $CFLAGS -c conftest.s 2>&1 | grep -i warning > /dev/null; then
+           libffi_cv_as_x86_64_unwind_section_type=no
+       fi
+       ])
+    if test "x$libffi_cv_as_x86_64_unwind_section_type" = xyes; then
+       AC_DEFINE(HAVE_AS_X86_64_UNWIND_SECTION_TYPE, 1,
+                 [Define if your assembler supports unwind section type.])
+    fi
+fi
+
 AC_CACHE_CHECK([whether .eh_frame section should be read-only],
     libffi_cv_ro_eh_frame, [
 	libffi_cv_ro_eh_frame=no
diff -up gcc-4.3.6/libffi/configure.unwind gcc-4.3.6/libffi/configure
--- gcc-4.3.6/libffi/configure.unwind	2011-06-27 13:28:31.000000000 +0200
+++ gcc-4.3.6/libffi/configure	2012-07-08 22:41:02.689711000 +0200
@@ -12522,6 +12522,31 @@ _ACEOF
     fi
 fi
 
+if test x$TARGET = xX86_64; then
+    echo "$as_me:$LINENO: checking assembler supports unwind section type" >&5
+echo $ECHO_N "checking assembler supports unwind section type... $ECHO_C" >&6
+if test "${libffi_cv_as_x86_64_unwind_section_type+set}" = set; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+
+       libffi_cv_as_x86_64_unwind_section_type=yes
+       echo '.section .eh_frame,"a",@unwind' > conftest.s
+       if $CC $CFLAGS -c conftest.s 2>&1 | grep -i warning > /dev/null; then
+           libffi_cv_as_x86_64_unwind_section_type=no
+       fi
+
+fi
+echo "$as_me:$LINENO: result: $libffi_cv_as_x86_64_unwind_section_type" >&5
+echo "${ECHO_T}$libffi_cv_as_x86_64_unwind_section_type" >&6
+    if test "x$libffi_cv_as_x86_64_unwind_section_type" = xyes; then
+
+cat >>confdefs.h <<\_ACEOF
+#define HAVE_AS_X86_64_UNWIND_SECTION_TYPE 1
+_ACEOF
+
+    fi
+fi
+
 echo "$as_me:$LINENO: checking whether .eh_frame section should be read-only" >&5
 echo $ECHO_N "checking whether .eh_frame section should be read-only... $ECHO_C" >&6
 if test "${libffi_cv_ro_eh_frame+set}" = set; then
diff -up gcc-4.3.6/libffi/fficonfig.h.in.unwind gcc-4.3.6/libffi/fficonfig.h.in
--- gcc-4.3.6/libffi/fficonfig.h.in.unwind	2011-06-27 13:28:31.000000000 +0200
+++ gcc-4.3.6/libffi/fficonfig.h.in	2012-07-08 22:40:32.000000000 +0200
@@ -37,6 +37,9 @@
    */
 #undef HAVE_AS_SPARC_UA_PCREL
 
+/* Define if your assembler supports unwind section type. */
+#undef HAVE_AS_X86_64_UNWIND_SECTION_TYPE
+
 /* Define to 1 if you have the <dlfcn.h> header file. */
 #undef HAVE_DLFCN_H
 
diff -up gcc-4.3.6/libffi/src/x86/unix64.S.unwind gcc-4.3.6/libffi/src/x86/unix64.S
--- gcc-4.3.6/libffi/src/x86/unix64.S.unwind	2005-05-05 06:06:38.000000000 +0200
+++ gcc-4.3.6/libffi/src/x86/unix64.S	2012-07-08 22:33:05.996220000 +0200
@@ -326,7 +326,11 @@ ffi_closure_unix64:
 .LUW9:
 	.size	ffi_closure_unix64,.-ffi_closure_unix64
 
+#ifdef HAVE_AS_X86_64_UNWIND_SECTION_TYPE
+	.section	.eh_frame,"a",@unwind
+#else
 	.section	.eh_frame,"a",@progbits
+#endif
 .Lframe1:
 	.long	.LECIE1-.LSCIE1		/* CIE Length */
 .LSCIE1: