Fix handling the -C option by recording the absolute path to the original script directory.
Fix handling the -C option by recording the absolute path to
the original script directory.

andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons,timj/scons,timj/scons,timj/scons,timj/scons,timj/scons,andrewyoung1991/scons,timj/scons,andrewyoung1991/scons,andrewyoung1991/scons,andrewyoung1991/scons,timj/scons,timj/scons,andrewyoung1991/scons