Bug 228601

Prior to GCC 11, these were good warnings that could catch serious errors. But GCC 11 has just become too sensitive and it's flagging what appear to be harmless cases, and not providing enough feedback to know why. This has resulted in me littering our code with pragmas to suppress GCC's false positives, and I think it's reached the point where it's nicer to just turn off the warnings until such time that GCC gets this under control, and rely on Clang instead in the meantime. The GCC developers have indicated that these warnings will *always* produce false positives in some circumstances, but with GCC 11 it's just too become too much IMO.