- Reduce false positives in cases of unknown soname
  - Make library extension regular expressions match only at end of string
  - When linking to libraries in implicit dirs convert to the -l option
    only if the file name is one that can be found by the linker
    (ex. /usr/lib/libfoo.so.1 should be linked by full path)
  - Add cmSystemTools::GuessLibrarySOName to guess the soname of a
    library based on presence of a symlink
  - In cmComputeLinkInformation try to guess an soname before assuming
    that a third-party library is built without an soname
  - In cmOrderDirectories guess the soname of shared libraries in cases
    it is otherwise unknown