I got hit by weird behavior while installing some package (as root). In shell environment, the variable GZIP=-9 is set and exported. The package Makefile contains something like this:
GZIP = /bin/gzip target: dep somecmd $< | $(GZIP) -9 > $@ Apparently, gmake exports the variables that were exported in the first place, thus gzip is invoked with "GZIP=/bin/gzip" in its env. The result being zero- length target _and_ gzip executable compressed into gzip.gz. Now this can be seen as outrageously funny, but I wonder...