Original commit message from CVS:
Mass change to support compiling for both 0.6 and 0.7. Common support is now
in common.{defs,override,c,h}. Specific version support is in
{0.6,0.7}.{defs,override,c,h}. The common and version specific files are
merged and/or used as needed.
common.override: add gst_version
