The C Runtime In Tcl is a self-contained package to build C code
into an extension on the fly. It is somewhat inspired by Brian
Ingerson's Inline for Perl, but Critcl is considerably more
lightweight.
The idea is to wrap C code into something that will compile into a
Tcl extension, and then also fire up the compiler. Compiled chunks
will be cached in your ~/.critcl/ directory, so subsequent use will
be instant.