The wart util is used at build time only, so use BUILD_* so we can cross-compile.
--- a/makefile
+++ b/makefile
@@ -1478,8 +1478,13 @@ ckcmai.$(EXT): ckcmai.c ckcker.h ckcdeb.h ckcsym.h ckcasc.h ckcnet.h ckcsig.h \
 
 ckclib.$(EXT): ckclib.c ckclib.h ckcdeb.h ckcasc.h ckcsym.h ckcfnp.h
 
+BUILD_CC ?= $(CC)
+BUILD_CFLAGS ?= $(CFLAGS)
+BUILD_CPPFLAGS ?= $(CPPFLAGS)
+BUILD_LDFLAGS ?= $(LDFLAGS)
+
 wart: ckwart.$(EXT)
-	$(CC) $(LNKFLAGS) -o wart ckwart.$(EXT) $(LIBS)
+	$(BUILD_CC) $(BUILD_CFLAGS) $(BUILD_CPPFLAGS) -o wart ckwart.$(EXT) $(BUILD_LDFLAGS)
 
 ckcpro.c: ckcpro.w wart ckcdeb.h ckcsym.h ckcasc.h ckcker.h ckcnet.h ckctel.h \
 	 ckclib.h