-fvisibility=hidden is no longer a requirement for dynamic X11.

We don't clash with Xlib symbols anymore.

--HG--
extra : rebase_source : 0efa50cb3e047dbfb0bdf0fd804a86c819305b83
Fixed SONAME lookup for runtime loading of shared libraries in CMake project.

Fixes Bugzilla #2249.

--HG--
extra : rebase_source : 5c636b43fb41bff6ecad963eafa6268d317403cd