--- a/sys/unix/GNUmakefile
+++ b/sys/unix/GNUmakefile
@@ -21,12 +21,16 @@
 TOUCH_VARDATA += $(if $(GAMEUID),&& chown $(GAMEUID) $(1))
 TOUCH_VARDATA += $(if $(GAMEGID),&& chgrp $(GAMEGID) $(1))
 
-CFLAGS = -g -O2
+CFLAGS ?= -g -O2
 
-CPPFLAGS += -Iinclude
-CPPFLAGS += -DDLB
-CPPFLAGS += -DDLBFILE=\"nhdat\"
-CPPFLAGS += -DDLBAREA=FILE_AREA_SHARE
+COMMON_CPPFLAGS :=
+COMMON_CPPFLAGS += -Iinclude
+COMMON_CPPFLAGS += -DDLB
+COMMON_CPPFLAGS += -DDLBFILE=\"nhdat\"
+COMMON_CPPFLAGS += -DDLBAREA=FILE_AREA_SHARE
+
+CPPFLAGS += $(COMMON_CPPFLAGS)
+CPPFLAGS_FOR_BUILD += $(COMMON_CPPFLAGS)
 
 GAMELIBS = -lncurses
 
@@ -88,28 +92,31 @@
 	$(CC) $(LDFLAGS) $^ $(LDLIBS) $(GAMELIBS) -o $@
 AUTO_BIN += src/$(GAME)
 
-MAKEDEFS_O = util/makedefs.o src/alloc.o src/monst.o src/objects.o	\
+util/%.o: util/%.c
+	$(CC_FOR_BUILD) $(CPPFLAGS_FOR_BUILD) $(CFLAGS_FOR_BUILD) $< -c -o $@
+
+MAKEDEFS_O = util/makedefs.o util/alloc.o util/monst.o util/objects.o	\
              util/panic.o
 util/makedefs: $(MAKEDEFS_O)
-	$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@
+	$(CC_FOR_BUILD) $(LDFLAGS_FOR_BUILD) $^ -o $@
 AUTO_BIN += util/makedefs
 
-DLB_O = util/dlb_main.o src/alloc.o src/dlb.o util/panic.o
+DLB_O = util/dlb_main.o util/alloc.o util/dlb.o util/panic.o
 util/dlb: $(DLB_O)
-	$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@
+	$(CC_FOR_BUILD) $(LDFLAGS_FOR_BUILD) $^ -o $@
 AUTO_BIN += util/dlb
 
 DGN_COMP_O = util/dgn_main.o util/dgn_lex.o util/dgn_yacc.o	\
-             src/alloc.o util/panic.o
+             util/alloc.o util/panic.o
 util/dgn_comp: $(DGN_COMP_O)
-	$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@
+	$(CC_FOR_BUILD) $(LDFLAGS_FOR_BUILD) $^ -o $@
 AUTO_BIN += util/dgn_comp
 
 LEV_COMP_O = util/lev_main.o util/lev_lex.o util/lev_yacc.o	\
-             src/alloc.o src/decl.o src/drawing.o src/monst.o	\
-             src/objects.o util/panic.o
+             util/alloc.o util/decl.o util/drawing.o util/monst.o	\
+             util/objects.o util/panic.o
 util/lev_comp: $(LEV_COMP_O)
-	$(CC) $(LDFLAGS) $^ $(LDLIBS) -o $@
+	$(CC_FOR_BUILD) $(LDFLAGS_FOR_BUILD) $^ -o $@
 AUTO_BIN += util/lev_comp
 
 ALL_O = $(GAME_O) $(MAKEDEFS_O) $(DLB_O) $(DGN_COMP_O) $(LEV_COMP_O)