I figured out the problem right after sending this: when I set $CC, it overwrites the makefile variable that tells it to use lpgcc, so lpgcc isn't getting used.
I changed all occurrences of "CC" in the tint makefile to "MYCC", and it compiled correctly.
Is there a less hackish way I should solve it, and then submit a patch? Or does someone who knows what they're doing better want to take care of it?