RFA: Fix target/44750

[Joern Rennecke]

Quoting Paul Koning <paul_koning@dell.com>:

> Joern,
>
> I ran into a problem with this.

Oops, while we can rely on a fairly recent version of GNU make, the same
is not true of the bootstrap compiler.  So there is still a good reason
to stick to the *.o-warn mechanism.

The attached patch makes use of this so that we use just -Wno-error, and only
when we're actually using -Werror in the first place.

OK to apply?


-------------- next part --------------
2010-11-05  Joern Rennecke  <amylaar@spamcop.net>

	 PR target/44750
        * config/pdp11/t-pdp11 (dwarf2out.o, java/constants.o): Undo last
	change.  Set $@-warn.o to -Wno-error.

Index: config/pdp11/t-pdp11
===================================================================
--- config/pdp11/t-pdp11	(revision 166331)
+++ config/pdp11/t-pdp11	(working copy)
@@ -39,8 +39,10 @@ MULTILIB_OPTIONS = msoft-float
 # DWARF_ARANGES_PAD_SIZE is 0, thus a loop in output_aranges that checks
 # (i < (unsigned) DWARF_ARANGES_PAD_SIZE) elicits a warning that the
 # comparison is always false.
-dwarf2out.o: ALL_COMPILERFLAGS += -Wno-error=type-limits
+# We could say "-Werror -Wno-error=type-limits", alas, not all supported
+# gcc bootstrap compilers support the latter option.
+dwarf2out.o-warn = -Wno-error
 
 # Likewise, java/constants.c:build_constants_constructor has a negative shift
 # count (in never-executed code) due to the small POINTER_SIZE.
-java/constants.o: ALL_COMPILERFLAGS += -Wno-error
+java/constants.o-warn = -Wno-error