Build if GETC_MACRO use is disabled

libc/stdio/gets.c

@@ -13,7 +13,11 @@ link_warning(gets, "the 'gets' function is dangerous and should not be used.")
 
 libc_hidden_proto(getchar_unlocked)
 libc_hidden_proto(__fgetc_unlocked)
+#ifdef __STDIO_GETC_MACRO
 libc_hidden_proto(__stdin)
+#else
+#define __stdin stdin
+#endif
 
 char *gets(char *s)
 {