Bug: https://bugs.gentoo.org/910494
--- a/XMPFiles/source/PluginHandler/XMPAtoms.h
+++ b/XMPFiles/source/PluginHandler/XMPAtoms.h
@@ -83,8 +83,12 @@ enum
 
 #define XMPAtomNull emptyStr_K
 
-struct StringCompare : std::binary_function<const std::string &, const std::string &, bool>
+struct StringCompare
 {
+	public:
+		using first_argument_type = const std::string &;
+		using second_argument_type = const std::string &;
+		using result_type = bool;
 	bool operator() (const std::string & a, const std::string & b) const
 	{
 		return ( a.compare(b) < 0 );
--- a/XMPFilesPlugins/api/source/PluginRegistry.h
+++ b/XMPFilesPlugins/api/source/PluginRegistry.h
@@ -68,8 +68,12 @@ public:
 	
 private:
 
-	struct StringCompare : std::binary_function< const std::string &, const std::string &, bool >
+	struct StringCompare
 	{
+		public:
+			using first_argument_type = const std::string &;
+			using second_argument_type = const std::string &;
+			using result_type = bool;
 		bool operator()( const std::string & a, const std::string & b ) const
 		{
 			return ( a.compare(b) < 0 );