Define __STDC_HOSTED__

Quoting Michael Matz on tinycc-devel:

"__STDC_HOSTED__  : not set (incorrectly, it should probably be set to 1
                    given that tcc assumes a normal main() and that the
                    rest of the provided facilities is provided by the C
                    library not under tcc control)"

libtcc.c

@@ -924,6 +924,7 @@ LIBTCCAPI TCCState *tcc_new(void)
     /* standard defines */
     tcc_define_symbol(s, "__STDC__", NULL);
     tcc_define_symbol(s, "__STDC_VERSION__", "199901L");
+    tcc_define_symbol(s, "__STDC_HOSTED__", NULL);
 
     /* target defines */
 #if defined(TCC_TARGET_I386)