Fix warnings.

* ser_avrdoper.c: add <stdlib.h> so exit() is declared.
* usbtiny.c (usbtiny_open): provide an initializer to a
"may be used uninitialized" variable (since GCC could not
fully detect the logic behind).



git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk/avrdude@981 81a1dc3b-b13d-400b-aceb-764788c761c2

ser_avrdoper.c

@@ -31,6 +31,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <stdlib.h>
 
 #include "avrdude.h"
 #include "serial.h"