diff --git a/src/Fl_Native_File_Chooser_GTK.cxx b/src/Fl_Native_File_Chooser_GTK.cxx
index 30b2fde6e..e9decde1e 100644
--- a/src/Fl_Native_File_Chooser_GTK.cxx
+++ b/src/Fl_Native_File_Chooser_GTK.cxx
@@ -879,7 +879,7 @@ return; }
  */
 void Fl_GTK_Native_File_Chooser_Driver::probe_for_GTK_libs(void) {
   void  *ptr_gtk;
-  if ( !Fl_X11_System_Driver::probe_for_GTK(2, 4, &ptr_gtk)) {
+  if ( !Fl_Posix_System_Driver::probe_for_GTK(2, 4, &ptr_gtk)) {
     did_find_GTK_libs = 0;
     return;
   }
diff --git a/src/drivers/Posix/Fl_Posix_Printer_Driver.cxx b/src/drivers/Posix/Fl_Posix_Printer_Driver.cxx
index 904c6d334..b93a5ec28 100644
--- a/src/drivers/Posix/Fl_Posix_Printer_Driver.cxx
+++ b/src/drivers/Posix/Fl_Posix_Printer_Driver.cxx
@@ -98,7 +98,7 @@ void *Fl_GTK_Printer_Driver::ptr_gtk = NULL;
 
 // test wether GTK is available at run-time
 bool Fl_GTK_Printer_Driver::probe_for_GTK() {
-  return Fl_X11_System_Driver::probe_for_GTK(2, 10, &ptr_gtk);
+  return Fl_Posix_System_Driver::probe_for_GTK(2, 10, &ptr_gtk);
 }