nsparently but it can cause problems
for programs that are being built with an SDK and searching
for specific libraries.  Callers of find_library_file need to
keep in mind that the base filename of the returned SDK library
file might have a different extension from that of the library
file installed on the running system, for example:
  /Applications/Xcode.app/Contents/Developer/Platforms/
      MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/
      usr/lib/libedit.tbd
vs
  /usr/lib/libedit.dylib
