>pkgsrc/security/libcrack/patch-ab patches a Makefile to use:

> ${LIBTOOL} --mode=compile ${CC} ${CFLAGS} ${.IMPSRC} -c -o ${.TARGET}

.IMPSRC, .TARGET etc are bmake aliases for < and @.  They mean nothing
outside of bmake.  For portable makefiles one should use @,?,>,<,*

>I think these local variables are not in GNU make. And for some reason
>aren't working with the bmake.

Are you sure about the last?

>I could not reproduce under NetBSD.

Good ;-)

>Any comments before I add my patch-ab fix to the pkg/20843?

If the makefile should work with something other than BSD make, then
.TARGET, .IMPSRC, .ALLSRC, .PREFIX et al should be avoided.

--sjg