ruserpass.c: needs stdio_ext.h only if threads are enabled

Signed-off-by: Peter S. Mazinger <ps.m@gmx.net>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

libc/inet/rpc/ruserpass.c

@@ -35,7 +35,9 @@
 #include <errno.h>
 #include <netdb.h>
 #include <stdio.h>
-#include <stdio_ext.h>
+#ifdef __UCLIBC_HAS_THREADS__
+# include <stdio_ext.h>
+#endif
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>