Check if compiler supports libFuzzer and sanitizer specific flags
Check if compiler supports libFuzzer and sanitizer specific flags

This allows to build most parts with both gcc and clang.

Change-Id: I6fbdedfcb492f48b46f9f35018c9c3f9fd48820d
Reviewed-on: https://team-review.git.corp.google.com/58604
Reviewed-by: Vitaly Buka <30899b7d84d75ec2c2b981c63ebe46fea5c02e99@google.com>

vitalybuka/libprotobuf-mutator,vitalybuka/libprotobuf-mutator,google/libprotobuf-mutator,google/libprotobuf-mutator