FIX: Issue where empty variable would break configure script.
FIX: Issue where empty variable would break configure script.

--HG--
branch : v0-7

cbeck88/cegui-mirror-two,cbeck88/cegui-mirror-two,cbeck88/cegui-mirror-two,cbeck88/cegui-mirror-two,cbeck88/cegui-mirror-two