In various situations we want to figure out what type of compiler we
have, because we want to know stuff like "is it the pgi one", or "does
it use msvc style". The compiler object has this property already, via
an API specifically designed to communicate this info, but instead we
performed isinstance checks on a compiler class.
This is confusing and indirect, and has the side effect of requiring
more imports everywhere. We should do away with it.
Sometimes, the machine file can include compiler command line options,
in order to pick the correct multilib. For example, Meson uses "$cc
--print-search-dirs" to find the library search path, where $cc is the
cc from the machine file. Because the outputs of "gcc -m32
--print-search-dirs" and "gcc --print-search-dirs" are different, this
only works if you have
[binaries]
cc = ['gcc', '-m32']
in the machine file. Right now, however, the cmake module assumes that
the compiler listed in the machine file is either a compiler, or a
"launcher" followed by the compiler. Check if the second argument
starts with a slash (for Microsoft-like compilers) or a dash (for
everyone else), and if so presume that the CMAKE_*_COMPILER_LAUNCHER
need not be defined.