Remove GCC version limitation.
This was needed for some C++ features which are no longer used.
@@ -128,11 +128,4 @@ TCODLIB_CAPI int TCOD_strncasecmp(const char *s1, const char *s2, size_t n);
#ifdef _WIN32
#define vswprintf _vsnwprintf /* Windows */
#endif /* _WIN32 */
-
-#if defined(__GNUC__) && !defined(__clang__)
-#if __GNUC__ < 6 || (__GNUC__ == 6 && __GNUC_MINOR__ < 1)
-#error "GCC must be version 6.1 or later."
-#endif
-#endif
-
#endif /* LIBTCOD_PORTABILITY_H */
