The code for GetNPCType is bracketed with #ifdef ZONE / #endif
For some reason, -DZONE is missing from your COPTS statement in the makefile, so GetNPCType is not getting compiled. Here's what mine is (unaltered from the distributed code on biosprite):
Code:
COPTS=$(WFLAGS) -O2 -ggdb -pthread -pipe -D_GNU_SOURCE -DINVERSEXY -DFX -DZONE $(DFLAGS) $(MYSQL_FLAGS)