Add true/false to core.h.

core.h

@@ -3,6 +3,14 @@
 
 /* ---- Types ---------------------------------------------------------- */
 
+#ifndef TRUE
+#define TRUE 1
+#endif
+
+#ifndef FALSE
+#define FALSE 0
+#endif
+
 typedef unsigned char       U8;
 typedef unsigned short     U16;
 typedef unsigned int       U32;