biology/abyss: fix build on big-endian architectures

Use new GCC from ports on GCC architectures.

Merge 25eb9d2a914fb211fdfe04fcda5593f29fd23ff5, fixes build on GCC architectures.

Also include sys/endian.h and use bswap32 and bswap64 for byte-swapping (PR at https://github.com/bcgsc/abyss/pull/287 ).

PR: 238737
Approved by: yuri (maintainer), mat (mentor)
Differential Revision: https://reviews.freebsd.org/D20717