Subject: xwidgets build fails if webkit not present

From: Glenn Morris <[email-masked]>
Date: Wed, 20 Jan 2016 14:29:17 -0500

Package: emacs
Version: 25.1.50

Current emacs-25 branch compilation fails if configured --with-xwidgets
without webkit-devel installed:

  xwidget.c:100:34: fatal error: webkit/webkitwebview.h: No such file or directory

There's a ton of webkit-specific stuff in xwidget.c, but HAVE_WEBKIT_OSR
is used in only one place.

Either it should be used in more places, or configure should require
webkit for xwidgets (in which case HAVE_WEBKIT_OSR should just be
removed).