RFR (s) 8141570: Fix Zero interpreter build for --disable-precompiled-headers

[Kim Barrett]

On Nov 16, 2015, at 10:23 PM, Coleen Phillimore <coleen.phillimore at oracle.com> wrote:
> 
> I was trying to find if -Wundef wasn't an option supported in CLANG but undef is a hard thing to google for.

Oh, right, the problem might be that -W[no-]undef causes llvm to complain.

That is more difficult to deal with.  Not completely ideal, but something like

ifneq (,$(filter -Wundef, $(WARNING_FLAGS))
INCOMING_WARNING_FLAGS := $(WARNING_FLAGS)
WARNING_FLAGS = $(filter-out -Wundef, $(INCOMING_WARNING_FLAGS))
endif

Or alternatively, clobber WARNING_FLAGS as before only if using clang, and use the proposed new code if not, and let someone who cares about the combination of zero / linux / clang improve that part.