Control optional Xinerama support
Review Request #104698 - Created April 23, 2012 and submitted
Xinerama libraries are currently only used by ksplash, and detection is automagic. This patch adds an option allowing compile without Xinerama even if it's installed, defaulting to ON as to not change existing behaviour.
Configures and compiles fine, and scanelf reports Xinerama link when compiled with -DWITH_XINERAMA=ON, and no link when off.