DEBUG_FILES_CFLAGS contains the compiler debugging flag(s) used when
standlone debug files (/usr/lib/debug/...) are enabled. However,
archives for static linking (.a files) do not use standalone debug, and
should not have these flag(s) applied.
Archives were previously built with debug info, but that was an
unintentional side effect of the WITH_DEBUG_FILES knob. With this
change they will no longer be built with debug info by default.
We may want to revisit default debug info for archives, but it should
not be controlled by WITH_DEBUG_FILES.
Sponsored by: The FreeBSD Foundation