-fomit-frame-pointer in sys.mk

[coypu%sdf.org@localhost]

share/mk/sys.mk:
.elif !empty(MACHINE_ARCH:Maarch64*)
DBG?=   -O2 ${"${.TARGET:M*.po}" == "":? -fomit-frame-pointer:}
.else
DBG?=   -O2
.endif


This is leaking into pkgsrc packages, and causing problems (see
ruby*-base/hacks.mk).

Any ideas what to do with this?

I suspect this change is due to how clang used to emit frame pointer
code all the time for NetBSD, it no longer does this, also we are not
using clang.

(Original change to sys.mk from 2014, clang change from 2018).

I think that we should stop special casing aarch64 here.