Hi:
http://dynamo.iro.umontreal.ca/~gambit/wiki/index.php/Watcom_Makefile_Proced... (written in Scheme) creates an OpenWatcom makefile that has rules for a static library. An example at the bottom of the page shows how to link everything for application.exe
As stated in Gambit docs, Watcom is slower than GCC. However, one can still devel with Watcom and tinker with that quirky Msys-mingw only if optimization is necessary at the end of a project.
Cheers, -Bob-