Release binaries build on Travis (x86_64) don't work on other x86_64 machines.

[Zubnix]

It seems some excessive(?) subarch specific optimizations are enabled when building a release binary. This causes a SIGILL for me when I try to use binaries build on Travis (x86_64, ubuntu 14.04) on my staging server (also x86_64, debian buster). If I buid the binaries directly on my staging server, everything works just fine.

Unfortunately I'm not sure which optimizations flags cause this. I have quite a few other native modules as well, and the issue (SIGILL) only happens with fastcall (both ref.node & fastcall.node)