Post #2279973

@vathpela@infosec.exchange @karolherbst@chaos.social I totally disagree with both of these things. I agree with the stability of the api/abi though. For one clang has never implemented full gcc 4.2 behavior. So you can just ignore that right out the story. Second there are things that should never have been extension but were. E.g. casts as lvalues. Do you really want to support those still? Also do you really want to carry along gcc 3.3 c++ behavior of not doing adl correctly for templates or even gcc 2.95.3 no namespace behavior? The issue with some behavior changes in c++ is to change incorrectly rejected code; sfinae can cause this issue. Now on to c side of things (besides casts as lvalues extension which I suspect most folks have already forgotten about), there is less changes here that would cause an issue in fact there are options to allow the old compile just need to use -std=gnu90 and a few options -Wno- options. As for the current warnings and such are done to improve security and static type safety.