[Driver] Add ClangFlags::TargetSpecific to simplify err_drv_unsupported_opt_for_target processing
clang/lib/Driver/ToolChains/Clang.cpp has a lot of fragments like the following:
```
if (const Arg *A = Args.getLastArg(...)) {
if (Triple is xxx)
A->render(Args, CmdArgs);
else
D.Diag(diag::err_drv_unsupported_opt_for_target) << ...;
}
```
The problem is more apparent with a recent surge of AIX-specific options.
Introduce the TargetSpecific flag so that we can move the target-specific
options to ToolChains/*.cpp and ToolChains/Arch/*.cpp and overload the
warn_drv_unused_argument mechanism to give an err_drv_unsupported_opt_for_target
error.
Migrate -march=/-mcpu= and some AIX-specific options to use this simplified pattern.
Reviewed By: jansvoboda11
Differential Revision: https://reviews.llvm.org/D151590
GitOrigin-RevId: fbea5aada14315da14c2e296831b1cb1cc1ddd61
10 files changed
