Make linkfile symlinks relative

The source (target) of the symlink is specified relative to a project
within a tree, and the destination is specified relative to the top
of the tree, so it should always be possible to create a relative symlink
to the target file.  Relative symlinks will allow moving an entire tree
without breaking the symlink, and copying a tree (with -p) without leaving
a symlink to the old tree.

Change-Id: I16492a8b59a137d2abe43ca78e3b212e2c835599
1 file changed