cmOutputConverter: Let cmOutputConverterIsShellOperator accept cm::string_view

Source/cmOutputConverter.cxx

@@ -53,9 +53,9 @@ std::string cmOutputConverter::ConvertToOutputFormat(const std::string& source,
 }
 
 std::string cmOutputConverter::ConvertDirectorySeparatorsForShell(
-  const std::string& source) const
+  cm::string_view source) const
 {
-  std::string result = source;
+  std::string result(source);
   // For the MSYS shell convert drive letters to posix paths, so
   // that c:/some/path becomes /c/some/path.  This is needed to
   // avoid problems with the shell path translation.

Source/cmOutputConverter.h

@@ -25,8 +25,7 @@ public:
   };
   std::string ConvertToOutputFormat(const std::string& source,
                                     OutputFormat output) const;
-  std::string ConvertDirectorySeparatorsForShell(
-    const std::string& source) const;
+  std::string ConvertDirectorySeparatorsForShell(cm::string_view source) const;
 
   //! for existing files convert to output path and short path if spaces
   std::string ConvertToOutputForExisting(const std::string& remote,