Building Typica with make:

real: 0m30.067s
user: 0m29.518s
sys: 0m1.088s

with make -j 6:

real: 0m20.579s
user: 0m35.057s
sys: 0m1.404s

with make -j 12:

real: 0m20.260s
user: 0m39.467s
sys: 0m1.794s

I'd probably get bigger gains if my source files were smaller and more numerous.