ENH: make sure include and lib dirs are unix paths

Source/cmIncludeDirectoryCommand.cxx

@@ -39,7 +39,9 @@ bool cmIncludeDirectoryCommand::InitialPass(std::vector<std::string> const& args
       {
       cmSystemTools::Error("Empty Include Directory Passed into INCLUDE_DIRECTORIES command.");
       }
-    this->Makefile->AddIncludeDirectory((*i).c_str(), before);
+    std::string unixPath = *i;
+    cmSystemTools::ConvertToUnixSlashes(unixPath);
+    this->Makefile->AddIncludeDirectory(unixPath.c_str(), before);
     }
   return true;
 }

Source/cmLinkDirectoriesCommand.cxx

@@ -27,7 +27,9 @@ bool cmLinkDirectoriesCommand::InitialPass(std::vector<std::string> const& args)
   for(std::vector<std::string>::const_iterator i = args.begin();
       i != args.end(); ++i)
     {
-    this->Makefile->AddLinkDirectory((*i).c_str());
+    std::string unixPath = *i;
+    cmSystemTools::ConvertToUnixSlashes(unixPath);
+    this->Makefile->AddLinkDirectory(unixPath.c_str());
     }
   return true;
 }