RFA: update name of glibc PLT fixup function

[Jim Blandy <jimb@codesourcery.com>]

No regressions on FC6 IA-32.  But there are also no reports that this
is necessary.  Andreas Schwab simply pointed out that ld-linux.so
doesn't use 'fixup' any more, so I thought I'd be pro-active.

Okay to commit?

gdb/ChangeLog:
2007-01-03  Jim Blandy  <jimb@codesourcery.com>

	* glibc-tdep.c (glibc_skip_solib_resolver): Look for '_dl_fixup',
	then plain 'fixup'.

Index: gdb/glibc-tdep.c
===================================================================
RCS file: /cvs/src/src/gdb/glibc-tdep.c,v
retrieving revision 1.3
diff -u -r1.3 glibc-tdep.c
--- gdb/glibc-tdep.c	17 Dec 2005 22:34:00 -0000	1.3
+++ gdb/glibc-tdep.c	4 Jan 2007 00:02:22 -0000
@@ -90,8 +90,13 @@
 
   if (resolver)
     {
+      /* The dynamic linker began using this name in early 2005.  */
       struct minimal_symbol *fixup
-	= lookup_minimal_symbol ("fixup", NULL, objfile);
+	= lookup_minimal_symbol ("_dl_fixup", NULL, objfile);
+      
+      /* This is the name used in older versions.  */
+      if (! fixup)
+        fixup = lookup_minimal_symbol ("fixup", NULL, objfile);
 
       if (fixup && SYMBOL_VALUE_ADDRESS (fixup) == pc)
 	return frame_pc_unwind (get_current_frame ());