definitions for 'luai_writestring'/'luai_writeline'/'luai_writestringerror'

moved to 'lauxlib.h' (they do not need to be stable or configurable) +
prefixes changed from 'luai_' to 'lua_' (they are not part of the core)

lauxlib.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lauxlib.h,v 1.126 2014/10/01 11:54:56 roberto Exp roberto $
+** $Id: lauxlib.h,v 1.127 2014/10/25 11:50:46 roberto Exp roberto $
 ** Auxiliary functions for building Lua libraries
 ** See Copyright Notice in lua.h
 */
@@ -204,6 +204,31 @@ LUALIB_API void (luaL_openlib) (lua_State *L, const char *libname,
 #endif
 
 
+/*
+** {==================================================================
+** "Abstraction Layer" for basic report of messages and errors
+** ===================================================================
+*/
+
+/* print a string */
+#if !defined(lua_writestring)
+#define lua_writestring(s,l)   fwrite((s), sizeof(char), (l), stdout)
+#endif
+
+/* print a newline and flush the output */
+#if !defined(lua_writeline)
+#define lua_writeline()        (lua_writestring("\n", 1), fflush(stdout))
+#endif
+
+/* print an error message */
+#if !defined(lua_writestringerror)
+#define lua_writestringerror(s,p) \
+        (fprintf(stderr, (s), (p)), fflush(stderr))
+#endif
+
+/* }================================================================== */
+
+
 /*
 ** {============================================================
 ** Compatibility with deprecated conversions