Optionally skip link dependencies on shared library files

Add target property LINK_DEPENDS_NO_SHARED and initialization variable
CMAKE_LINK_DEPENDS_NO_SHARED to enable this behavior.

Suggested-by: Leif Walsh <leif.walsh@gmail.com>

Source/cmComputeLinkInformation.h

@@ -82,6 +82,7 @@ private:
   // Configuration information.
   const char* Config;
   const char* LinkLanguage;
+  bool LinkDependsNoShared;
 
   // Modes for dealing with dependent shared libraries.
   enum SharedDepMode