webkit-gtk: work around Make bug by re-running make
GNU make 3.82 has a bug where it drops required dependencies.
https://bugs.webkit.org/show_bug.cgi?id=79498 is the WebKitGTK+
bug, and http://savannah.gnu.org/bugs/?30653 is the GNU Make bug.
Work around this by running make again if it fails just in case the failure is
due to the bug.
Based on a patch by Andreas Müller <schnitzeltony@googlemail.com>.
[ YOCTO #2816 ]
Signed-off-by: Ross Burton <ross.burton@intel.com>
