Fix C library addons extraction:
- renaming the dircetory in CT_ExtratAndPatch is wrong:
- patches against the C library addons may be build against the short *or* long name... :-(
- symlink is more robust, even if less nice
- renaming the directory _after_ CT_ExtractAndPatch is too late:
- if patches are against the short name, and we renamed too the long name, patches don't apply
- so we'll never reach the point where we rename