D lang compilers have an option -release (or similar) which turns off
asserts, contracts, and other runtime type checking. This patch wires
that up to the b_ndebug flag.
Fixes#7082
Handle clang's cl or clang-cl being in PATH, or set in CC/CXX
Future work: checking the name of the executable here seems like a bad idea.
These compilers will fail to be detected if they are renamed.
v2:
Update compiler.get_argument_type() test
Fix comparisons of id inside CCompiler, backends and elsewhere
v3:
ClangClCPPCompiler should be a subclass of ClangClCCompier, as well
Future work: mocking in test_find_library_patterns() is effected, as we
now test for a subclass, rather than self.id in CCompiler.get_library_naming()
Some compilers try very had to pretend they're another compiler (ICC
pretends to be GCC and Linux and MacOS, and MSVC on windows), Clang
behaves much like GCC, but now also has clang-cl, which behaves like MSVC.
This method provides an easy way to determine whether testing for MSVC
like arguments `/w1234` or gcc like arguments `-Wfoo` are likely to
succeed, without having to check for dozens of compilers and the host
operating system, (as you would otherwise have to do with ICC).