Add -Wgnu-empty-initializer to Clang builds to catch this issue in the future. Initialising arrays with empty braces is not part of the C standard and fails on MSVC. This commit should catch the issue earlier by detecting it in Clang.
PiperOrigin-RevId: 517373961
Change-Id: I518006e84151e8d5b45a7fe00ba7675dfb031ca0
Also unify warning options across Clang and GCC and fix minor issues that was surfaced by this.
PiperOrigin-RevId: 508619655
Change-Id: I59b777bf2dfea4422485670e2427c7d3f5cf6405
Since upgrading to Clang 15, abseil fails to build, because of abseil/abseil-cpp#1201.
PiperOrigin-RevId: 486190797
Change-Id: Ibaa1c03b8d21ae4a83c3825c8d56363aa2f89505