When fiddling with a pet project I noticed that the file containing implicit make rules, /usr/share/mk/sys.mk, doesn't use CPPFLAGS at all (nor do any of the other files in that directory, for that matter). Surely it's easy enough to add this (i.e. the implicit rule would become what's written below), so there must be a pressing reason why it's not done. Does anyone know?
Code:
.c.o:
${CC} ${CFLAGS} [highlight]${CPPFLAGS}[/highlight] -c ${.IMPSRC}
${CTFCONVERT_CMD}