My question – how do you actually trace this back to the target that generated this statement? In this case, the ghostscript Makefile is so convoluted that it goes through levels of indirection to get to this point, so grep is of limited help here.
So – why can’t make add (optionally, of course) a line number/file name combo to each of the statements that it executes – and as an additional option show the text of the makefile that is executing at the time?