Hey Chris! Nice to see you in the TCC mailing lists as well. :-)
Here are a couple of thoughts on your ideas.
First, compiling perl5 with tcc will not really give you any of the features of tcc. If it compiles (and it has a decent chance of doing that) It'll just produce a perl binary that runs slower.
I suspect that you probably want to jit-compile code using tcc. For the roots of that, see the test for libtcc:
http://repo.or.cz/w/tinycc.git/blob/HEAD:/tests/libtcc_test.c. That said, if you're working in Perl, you probably should look into a couple of packages that have already wrapped tcc up as a jit compiler, including (my) C::TinyCompiler (
https://metacpan.org/pod/C::TinyCompiler) and Steffen Mueller's XS::TCC (
https://metacpan.org/pod/XS::TCC).
Finally, you're probably interested in getting things working on Windows. I bet that Cygwin works just fine even with the current branch, but MinGW might give trouble. I spent some time making sure that Alien::TinyCC installs the necessary header files for MinGW, so if you install that (or C::TinyCompiler) then it should work correctly on both Cygwin and MinGW. I've not tried building with visual studio, but I don't think you use that on your end.
Let me know if you have more questions about Perl/tcc. This is a subject near and dear to my heart. :-)