libgo: additional type/const references in sysinfo.c

Add a few more explicit references to enumeration constants
(RUSAGE_SELF, DT_UNKNOWN) in sysinfo.c to insure that their hosting enums
are emitted into DWARF, when using a clang host compiler during
the gollvm build.

Updates golang/go#41382.
Updates golang/go#41404.

Change-Id: Id0ed7a82ae5dc98ccffa5269a7147e0171c9b0ea
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/254941
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Than McIntosh <thanm@google.com>
1 file changed