C++98 and C++03 are effectively aliases as far as Clang is concerned.
As such, allowing both std=c++98 and std=c++03 as Lit parameters is
just slightly confusing, but provides no value. It's similar to allowing
both std=c++17 and std=c++1z, which we don't do.
This was discovered because we had an internal bot that ran the test
suite under both c++98 AND c++03 -- one of which is redundant.
Differential Revision: https://reviews.llvm.org/D80926
Forcing -Werror and other warnings means that the test suite isn't
actually testing what most people are seeing in their code -- it seems
better and less arbitrary to compile these tests as close as possible
to the compiler default instead.
Removing -Werror also means that we get to differentiate between
diagnostics that are errors and those that are warnings, which makes
the test suite more precise.
Differential Revision: https://reviews.llvm.org/D76311
Too many warnings are being disabled too quickly. Warnings are
important to keeping libc++ correct. This patch re-enables two
warnings: -Wconstant-evaluated and -Wdeprecated-copy.
In future, all warnings disabled for the test suite should require
an attached bug. The bug should state the plan for re-enabling that
warning, or a strong case why it should remain disabled.