removed old build scripts
include gmp runtime in build
add missing source files to runtime build
removed unnecessary includes
use relative srcdir instead of absolute
removed PoSSO memory allocator

after a failed 1-hour attempt to get it to work, I have decided to give
up on this and focus on more important work. in the end, we could just
use boehm, no need to have our own set of half-working garbage
collectors.