#1 no support for Linux AMD64

[Tyler Mandry]

It compiles fine on an AMD64 system, but when I try to
run it:

$ ./nogravity
Segmentation fault

All the dependencies appear to be installed, and the
NOGRAVITY.RMX is in the same directory. I can use the
x86 binaries for now (I think), but in the future it
would be nice to have native 64-bit versions available
(especially for us Gentoo users).