[alpha] Don't force MIPS debugging on dwarf2.

[Richard Henderson]

commit bc207f644185c3889e38406e9552fc5d43e66af5
Author: Richard Henderson <r...@redhat.com>
Date:   Wed Jul 6 13:04:49 2011 -0700

    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.

diff --git a/gcc/config/alpha/elf.h b/gcc/config/alpha/elf.h
index 0293f26..8fa1745 100644
--- a/gcc/config/alpha/elf.h
+++ b/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