alpha-elf: Disable stabs debugging, and the mips sdb extensions.

In particular, the mips sdb extensions accidentally implied the
irix dwarf2 extensions and restrictions.  Disable stabs because
it's almost certainly untested for years.

        * config/alpha/elf.h (MIPS_DEBUGGING_INFO): Undef.
        (DBX_DEBUGGING_INFO): Undef.

From-SVN: r176021

gcc/ChangeLog

 2011-07-07  Richard Henderson  <rth@redhat.com>
 
+	* config/alpha/elf.h (MIPS_DEBUGGING_INFO): Undef.
+	(DBX_DEBUGGING_INFO): Undef.
+
+2011-07-07  Richard Henderson  <rth@redhat.com>
+
 	* dwarf2out.c (output_cfi_directive): Export.  Add FILE parameter.
 	Handle some opcodes specially for debugging.
 	* print-rtl.c: Include dwarf2out.h

gcc/config/alpha/elf.h

@@ -25,8 +25,9 @@ along with GCC; see the file COPYING3.  If not see
 
 /* ??? Move all SDB stuff from alpha.h to osf.h.  */
 #undef SDB_DEBUGGING_INFO
+#undef MIPS_DEBUGGING_INFO
+#undef DBX_DEBUGGING_INFO
 
-#define DBX_DEBUGGING_INFO 1
 #define DWARF2_DEBUGGING_INFO 1
 
 #undef  PREFERRED_DEBUGGING_TYPE