package/zziplib: create symlinks only if target is missing
Symlink creation to base file names is only needed for versioned libraries.
Modify CMake rules to prevent overwriting existing libraties with recursive
links.
Fixes the following autobuild failures:
http://autobuild.buildroot.net/results/dd1/dd1974dbc1a22a96a3cedb117417e66119821514/
http://autobuild.buildroot.net/results/df8/df8406402ccff7cec34ae5858b8da57d1a4ae9c1/
http://autobuild.buildroot.net/results/743/7433a2ad111e2f014c81f196d3d1e2f63dffa858/
http://autobuild.buildroot.net/results/79f/79f88e9ec14cda7d07cf689eee864791ba949892/
...
http://autobuild.buildroot.net/results/892/8922efbbbfe79e8286a411acce4086b5c77c57c0/
http://autobuild.buildroot.net/results/dfa/dfa8ade3a4c1750e6dd58e652f60af2a44f80dd8/
http://autobuild.buildroot.net/results/9cd/9cd4147486f32d642513ba14efca3a02d5745ab9/
Regression test cases:
http://autobuild.buildroot.net/results/ba7/ba711034c0abe980f677e26de41739223e2f66e9/
http://autobuild.buildroot.net/results/032/032aaff121fb114f388c67dbca3ad2b02f670e38/
http://autobuild.buildroot.net/results/6c5/6c56b645a2b723920f07b98474452824fba5e2c1/
Signed-off-by: Andreas Ziegler <br015@umbiko.net>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
(cherry picked from commit 3e15fe6a5e)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
