Don't link with win32gdi unless it's enabled.

src/conio/GNUmakefile

@@ -5,7 +5,9 @@ include $(SRC_ROOT)/build/Common.gmake	# defines clean and output directory rule
 CFLAGS += $(XPDEV-MT_CFLAGS) $(HASH_CFLAGS) $(ENCODE_CFLAGS) $(CIOLIB-MT_CFLAGS)
 
 ifeq ($(os),win32)
- OBJS	+=	$(MTOBJODIR)$(DIRSEP)win32gdi$(OFILE)
+ ifdef WITH_GDI
+  OBJS	+=	$(MTOBJODIR)$(DIRSEP)win32gdi$(OFILE)
+ endif
  OBJS	+=	$(MTOBJODIR)$(DIRSEP)SDL_win32_main$(OFILE)
  OBJS	+=	$(MTOBJODIR)$(DIRSEP)win32cio$(OFILE)
  OBJS	+=	$(MTOBJODIR)$(DIRSEP)ciolib_res$(OFILE)