Replace forcing weston to pixman for fallback to using EGL_SOFTWARE=1

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@3082 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9
Always handle the default.environment file (if it exists)

git-svn-id: https://rebeccablackos.svn.sourceforge.net/svnroot/rebeccablackos@3083 56e3d1a8-0179-4092-b3e2-9fbbcda0c0a9