we have a case where gcc is used as preprocessor/assembler combination
(i.e. for an .S file), and -g0 is explicitely passed to make it not
generate any debug information.  Unfortunately in that situation gcc (the
driver) still passes --gdwarf2 to GNU as, which was explicitely requested
not to happen.

This patch deactivates this if -g0 is seen in the command line in the same
ways its already deactivated for *cpp_option.

Bootstraping on x86 works, regtesting in progress.  Okay if it passes?


Ciao,
Michael.
       * gcc.c (ASM_DEBUG_SPEC): Test -g0.

Index: gcc/gcc.c
===================================================================
--- gcc/gcc.c.orig	2009-11-20 13:50:34.000000000 +0100
+++ gcc/gcc.c	2009-11-20 13:50:39.000000000 +0100
@@ -670,14 +670,14 @@ proper position among the other output f
      && defined(HAVE_AS_GDWARF2_DEBUG_FLAG) && defined(HAVE_AS_GSTABS_DEBUG_FLAG)
 #  define ASM_DEBUG_SPEC						\
       (PREFERRED_DEBUGGING_TYPE == DBX_DEBUG				\
-       ? "%{gdwarf-2*:--gdwarf2}%{!gdwarf-2*:%{g*:--gstabs}}" ASM_MAP	\
-       : "%{gstabs*:--gstabs}%{!gstabs*:%{g*:--gdwarf2}}" ASM_MAP)
+       ? "%{!g0:%{gdwarf-2*:--gdwarf2}%{!gdwarf-2*:%{g*:--gstabs}}}" ASM_MAP \
+       : "%{!g0:%{gstabs*:--gstabs}%{!gstabs*:%{g*:--gdwarf2}}}" ASM_MAP)
 # else
 #  if defined(DBX_DEBUGGING_INFO) && defined(HAVE_AS_GSTABS_DEBUG_FLAG)
-#   define ASM_DEBUG_SPEC "%{g*:--gstabs}" ASM_MAP
+#   define ASM_DEBUG_SPEC "%{g*:%{!g0:--gstabs}}" ASM_MAP
 #  endif
 #  if defined(DWARF2_DEBUGGING_INFO) && defined(HAVE_AS_GDWARF2_DEBUG_FLAG)
-#   define ASM_DEBUG_SPEC "%{g*:--gdwarf2}" ASM_MAP
+#   define ASM_DEBUG_SPEC "%{g*:%{!g0:--gdwarf2}}" ASM_MAP
 #  endif
 # endif
 #endif