When building Debian packages pre-processor flags are passed via
CPPFLAGS, as the convention indicates. Specifically, the hardening
-D_FORTIFY_SOURCE=2 flag is used.
Pass CPPFLAGS to all calls of QUIET_CC together with CFLAGS.
Signed-off-by: Luca Boccassi <bluca@debian.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>