paths relative to ${.CURDIR} instead. Using BSDSRCDIR here means that
it's impossible to compile these programs out of the source tree they're
a part of, unless that sort tree happens to be the one at BSDSRCDIR.
hack to enable this to work when included from a different directory.
Idea: if the crunchgen(1) child were to cd to the target directory
just prior to executing its manufactured Makefile, then problems
like this might not occur.