The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/1fd2b894ea70b4221dfd8e409f7b16b6208576fa

commit 1fd2b894ea70b4221dfd8e409f7b16b6208576fa
Author: Manoj Gupta <manojgupta@google.com>
Date: Tue May 15 15:33:54 2018

gcc/clang wrapper: Filter unsupported flags for sanitizer builds.

Some of the commonly used linker flags e.g. "-Wl,-z,def" or
"-Wl,--no-undefined" are not supported by sanitizers.
Since it may not be easy to fix each build to remove these flags,
filter them by detecting sanitizer usage in the clang wrappers.

Also filter "-Xcompiler" from GCC command line.

BUG= chromium:841847 
TEST=chromiumos-sdk builds.
TEST=amd64-generic-fuzzer builds are unaffected.
TEST=alsa-lib builds without complains about unreferenced symbols.

Change-Id: Idb4a9ac2726ab17abbc6680705e676d2a4816901
Reviewed-on: https://chromium-review.googlesource.com/1058110
Tested-by: Manoj Gupta <manojgupta@chromium.org>
Reviewed-by: Caroline Tice <cmtice@chromium.org>
Commit-Queue: Manoj Gupta <manojgupta@chromium.org>

[modify] https://crrev.com/1fd2b894ea70b4221dfd8e409f7b16b6208576fa/sys-devel/gcc/files/sysroot_wrapper.body
[rename] https://crrev.com/1fd2b894ea70b4221dfd8e409f7b16b6208576fa/sys-devel/llvm/llvm-7.0_pre328903_p20180425-r4.ebuild
[modify] https://crrev.com/1fd2b894ea70b4221dfd8e409f7b16b6208576fa/sys-devel/gcc/gcc-9999.ebuild
[modify] https://crrev.com/1fd2b894ea70b4221dfd8e409f7b16b6208576fa/sys-devel/llvm/files/wrapper_script_common
[modify] https://crrev.com/1fd2b894ea70b4221dfd8e409f7b16b6208576fa/sys-devel/llvm/files/clang_host_wrapper.body