[RFA] pdp11.c: Fix link errors

[Paul Koning <paul_koning at dell dot com>]

This patch cures two issues with linking for pdp11: 

When the program is larger than 32 kB, you'd get relocation truncated errors because the relocation overflow check was set to "signed", but "unsigned" is appropriate for pdp11.

When linking against libraries with debug symbols you'd sometimes get duplicate definition errors on names that are in fact stabs entries, not globals.  This is caused by code that looks for N_BSS|N_EXT entries, but that code point is used for N_FUN instead.

Tested by build for pdp11 target and check of the gcc testcase that caught this.

Ok to commit?

	paul

ChangeLog:

	* pdp11.c (howto_table_pdp11): Make overflow check unsigned.
	(translate_from_native_sym_flags, pdp11_aout_swap_reloc_out,
	aout_link_check_ar_symbols, aout_link_add_symbols): Remove case
	for N_BSS|N_EXT.

Index: pdp11.c
===================================================================
RCS file: /cvs/src/src/bfd/pdp11.c,v
retrieving revision 1.47
diff -u -r1.47 pdp11.c
--- pdp11.c	13 Dec 2010 01:06:15 -0000	1.47
+++ pdp11.c	28 Dec 2010 18:28:51 -0000
@@ -245,8 +245,8 @@
 reloc_howto_type howto_table_pdp11[] =
 {
   /* type              rs size bsz  pcrel bitpos ovrf                     sf name     part_inpl readmask  setmask    pcdone */
-HOWTO( 0,	       0,  1,  16,  FALSE, 0, complain_overflow_signed,0,"16",	TRUE, 0x0000ffff,0x0000ffff, FALSE),
-HOWTO( 1,	       0,  1,  16,  TRUE,  0, complain_overflow_signed,0,"DISP16",	TRUE, 0x0000ffff,0x0000ffff, FALSE),
+HOWTO( 0,	       0,  1,  16,  FALSE, 0, complain_overflow_unsigned,0,"16",	TRUE, 0x0000ffff,0x0000ffff, FALSE),
+HOWTO( 1,	       0,  1,  16,  TRUE,  0, complain_overflow_unsigned,0,"DISP16",	TRUE, 0x0000ffff,0x0000ffff, FALSE),
 };
 
 #define TABLE_SIZE(TABLE)	(sizeof(TABLE)/sizeof(TABLE[0]))
@@ -1345,7 +1345,7 @@
       cache_ptr->symbol.flags = visible;
       break;
 
-    case N_BSS: case N_BSS | N_EXT:
+    case N_BSS:
       cache_ptr->symbol.section = obj_bsssec (abfd);
       cache_ptr->symbol.value -= cache_ptr->symbol.section->vma;
       cache_ptr->symbol.flags = visible;
@@ -1757,7 +1757,6 @@
 	  cache_ptr->addend = ad - su->datasec->vma;			\
 	  break;							\
 	case N_BSS:							\
-	case N_BSS | N_EXT:						\
 	  cache_ptr->sym_ptr_ptr  = obj_bsssec (abfd)->symbol_ptr_ptr;	\
 	  cache_ptr->addend = ad - su->bsssec->vma;			\
 	  break;							\
@@ -2583,7 +2582,6 @@
 
       if (type == (N_TEXT | N_EXT)
 	  || type == (N_DATA | N_EXT)
-	  || type == (N_BSS | N_EXT)
 	  || type == (N_ABS | N_EXT))
 	{
 	  /* This object file defines this symbol.  We must link it
@@ -2822,10 +2820,6 @@
 	  section = obj_datasec (abfd);
 	  value -= bfd_get_section_vma (abfd, section);
 	  break;
-	case N_BSS | N_EXT:
-	  section = obj_bsssec (abfd);
-	  value -= bfd_get_section_vma (abfd, section);
-	  break;
 	}
 
       if (! ((*add_one_symbol)