C++ exceptions doesn't work in i386 shared libs when using sjlj exceptions

(as a.out does per default.)  This is because the compiler forgets to
restore the PIC register after a builtin_setjmp (i.e. when catching an
exception.)  This fix is taken from the gcc 2.95 branch.

Fixes PR#9110.

gnu/dist/gcc/config/i386/i386.md

@@ -7816,3 +7816,12 @@ byte_xor_operation:
   load_pic_register (1);
   DONE;
 }")
+
+(define_expand "builtin_setjmp_receiver"
+  [(label_ref (match_operand 0 "" ""))]
+  "flag_pic" 
+  "    
+{
+  load_pic_register (1);
+  DONE;
+}")