Clean up buildvm error message.

src/host/buildvm.c

@@ -424,7 +424,7 @@ int main(int argc, char **argv)
 
   if (sizeof(void *) != 4*LJ_32+8*LJ_64) {
     fprintf(stderr,"Error: pointer size mismatch in cross-build.\n");
-    fprintf(stderr,"Try: make HOST_CC=\"gcc -m32\" CROSS=... TARGET=...\n\n");
+    fprintf(stderr,"Try: make HOST_CC=\"gcc -m32\" CROSS=...\n\n");
     return 1;
   }