comms/flrig: Fix and improve the port
- Remove upstream site from MASTER_SITES as it seems to drop legacy versions.
- Remove the NATIVE menu option as it just adds -march=native, which CPUTYPE already does and is treewide. And it's also not supported across all ARCH-es.
https://sourceforge.net/p/fldigi/fldigi/ci/master/tree/m4/opt.m4
Reported by: diizzy@
Reviewed by: db@ (Mentor)
Approved by: yuri@ (Mentor)
Differential Revision: https://reviews.freebsd.org/D52030