Without having much knowledge about fortran in general, and
the differences between the two compilers in particular the
"R_X86_64_32" suggests that you're trying to mix 32 and 64 bit
code? Maybe you need to try architecture flags with the gnu
compiler, e.g. -mtune=k8 or try to find the 64-bit equivalent
(or 32, no idea which way around you're mixing) of whatever
you're linking against.