diff -r -u simutrans-src.orig/Makefile simutrans-src/Makefile
--- simutrans-src.orig/Makefile	2007-07-05 21:27:11.000000000 +0200
+++ simutrans-src/Makefile	2007-07-05 22:21:24.000000000 +0200
@@ -38,6 +38,7 @@
 endif
 
 ifeq ($(OSTYPE),linux)
+  CFLAGS   += -DUSE_C
   STD_LIBS ?= -lz
 endif
 
diff -r -u simutrans-src.orig/simvehikel.cc simutrans-src/simvehikel.cc
--- simutrans-src.orig/simvehikel.cc	2007-07-05 21:27:11.000000000 +0200
+++ simutrans-src/simvehikel.cc	2007-07-05 22:18:22.000000000 +0200
@@ -370,7 +370,7 @@
 	 * (the waggon_t::setze_convoi etc. routines must then remove a
 	 *  possibly pending reservation of stops/tracks)
 	 */
-	assert(  c==NULL  ||  ((unsigned)cnv<=1)  ||  c==cnv);
+	assert(  c==NULL  ||  ((uintptr_t)cnv<=1)  ||  c==cnv);
 	cnv = c;
 	if(cnv) {
 		// we need to reestablish the finish flag after loading