add libc building to agbcc.

libc/include/assert.h

@@ -0,0 +1,29 @@
+/*
+	assert.h
+*/
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "_ansi.h"
+
+#undef assert
+
+#ifdef NDEBUG           /* required by ANSI standard */
+#define assert(p)  	((void)0)
+#else
+
+#ifdef __STDC__
+#define assert(e)       ((e) ? (void)0 : __assert(__FILE__, __LINE__, #e))
+#else   /* PCC */
+#define assert(e)       ((e) ? (void)0 : __assert(__FILE__, __LINE__, "e"))
+#endif
+
+#endif /* NDEBUG */
+
+void _EXFUN(__assert,(const char *, int, const char *));
+
+#ifdef __cplusplus
+}
+#endif