diff --git a/MagickCore/gem-private.h b/MagickCore/gem-private.h
index 6c236bb..fce2351 100644
--- a/MagickCore/gem-private.h
+++ b/MagickCore/gem-private.h
@@ -32,10 +32,14 @@
   GetOptimalKernelWidth2D(const double,const double);
 
 extern MagickPrivate void
+  ConvertHCLToRGB(const double,const double,const double,double *,double *,
+    double *),
   ConvertHSBToRGB(const double,const double,const double,double *,double *,
     double *),
   ConvertHWBToRGB(const double,const double,const double,double *,double *,
     double *),
+  ConvertRGBToHCL(const double,const double,const double,double *,double *,
+    double *),
   ConvertRGBToHSB(const double,const double,const double,double *,double *,
     double *),
   ConvertRGBToHWB(const double,const double,const double,double *,double *,