* src/xwidget.c: Add missing header.

The header webkit/webkitwebpolicydecision.h is required for
`webkit_web_policy_decision_download'.
Merge branch 'jave-xwidget' into xwidget
* src/xwidget.c: Fix a lot of errors when compiling with --enable-checking
and --enable-check-lisp-object-type.
Merge pull request #3 from daimrod/fix-compile-time-errors

Fix compile time errors