The Quake III Arena sources as originally released under the GPL license on August 20, 2005.

lcc/include/x86/linux/assert.h

@@ -0,0 +1,14 @@
+#ifndef __ASSERT
+#define __ASSERT
+
+void assert(int);
+
+#endif /* __ASSERT */
+
+#undef assert
+#ifdef NDEBUG
+#define assert(ignore) ((void)0)
+#else
+extern int _assert(char *, char *, unsigned);
+#define assert(e) ((void)((e)||_assert(#e, __FILE__, __LINE__)))
+#endif /* NDEBUG */