meson: fix CC_VERSION.
The way we use CC_VERSION macro is to give information on the compiler used during build. This information may be useful when debugging in particular. So we can't just use `cc.version()` which only gives a version number, not even the name of the compiler. Restore the logics of autotools where we were using the result of `cc -v` (for gcc and clang) and testing various CLI options for other compilers. Also this test may fail on meson because of various bugs, which I now reported and provided patch for (hopefully soon merged). In particular, when using ccache, the command run fails (also I have to change newlines in C-style `\n` myself as meson's set_quoted() creates broken header when newlines are present). If it fails, let's at least store the compiler name + its version, still more useful than version only.
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