When I try to run meson with CC set to a C compiler it doesn't know about (for instance pcc, tcc, or others), I get the error

meson.build:1:0: ERROR: Unknown compiler(s): [['pcc']]

However, pcc follows the standard POSIX compiler interface, and is perfectly capable of building the project in question. There are quite a few C compilers in the world, and I think meson should allow the build to continue even if it doesn't know about the particular one the user specified.

Perhaps this could be done by falling back to a GenericPosixCCompiler, which supports the options specified in https://pubs.opengroup.org/onlinepubs/9699919799/utilities/c99.html.