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

usbtiny.c

@@ -197,7 +197,7 @@ static	int	usbtiny_open(PROGRAMMER* pgm, char* name)
 {
   struct usb_bus      *bus;
   struct usb_device   *dev = 0;
-  char *bus_name;
+  char *bus_name = NULL;
   char *dev_name = NULL;
 
   // if no -P was given or '-P usb' was given