suppress splitdebug for .o files

BUG=chromium-os:21932,chromium:305263
TEST=cbuildbot run of an arm builder, checking python.o after dump_syms
     runs against it
TEST=`emerge-x86-alex chromeos-kernel` no longer throws errors during stripping
TEST=`emerge-x86-alex chromeos-kernel` has split debug files for kernel modules
TEST=`emerge-x86-alex python` does not have debug file for python.o, and lacks debug sections
TEST=`emerge-x86-alex chromeos-base/autotest-deps-libaio` does not have debug file for raw_syscall.os, and lacks debug sections
TEST=`cros_generate_breakpad_symbols --board x86-alex` still works
https://gerrit.chromium.org/gerrit/10451
https://gerrit.chromium.org/gerrit/42997

Change-Id: I08aa03df98265a307ef1142ac0af722e8e1bd0cd
Reviewed-on: https://chromium-review.googlesource.com/214525
Tested-by: Bertrand Simonnet <bsimonnet@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed