try_run: Add support for LINK_LIBRARIES option.

Most functionality is already implemented in Source/cmCoreTryCompile.{h,cxx}.
Document and improve argument parsing.

This functionality is already being used by a number of modules, like
CheckCSourceCompiles.cmake, but it is not documented.

Source/cmCoreTryCompile.cxx

@@ -109,7 +109,7 @@ int cmCoreTryCompile::TryCompileCode(std::vector<std::string> const& argv)
               }
           default:
             this->Makefile->IssueMessage(cmake::FATAL_ERROR,
-              "Only libraries may be used as try_compile IMPORTED "
+              "Only libraries may be used as try_compile or try_run IMPORTED "
               "LINK_LIBRARIES.  Got " + std::string(tgt->GetName()) + " of "
               "type " + tgt->GetTargetTypeName(tgt->GetType()) + ".");
             return -1;