This is just a script, that invokes whichever compiler is set in the "CC" environment variable. If you set CC=tcc, it's basically the same as "tcc -run file.c", but I suppose this is a little bit nicer: "c file.c".

I would probably use this with Clang rather than TCC if Clang compiles fast enough, which it generally does.

If I understand it correctly, tcc is actually a compiler. C is just a script that compiles-then-runs, using whatever compiler you have set in your environment.