diff --git a/configure.in.in b/configure.in.in
index 97468718..ae82a862 100644
--- a/configure.in.in
+++ b/configure.in.in
@@ -232,7 +232,7 @@ AC_DEFUN([KDE_CHECK_MDI],
     AC_LANG_SAVE
     AC_LANG_CPLUSPLUS
     save_CXXFLAGS="$CXXFLAGS"
-    CXXFLAGS="$KDE_INCLUDES $QT_INCLUDES $all_includes"
+    CXXFLAGS="$KDE_INCLUDES $TQT_INCLUDES $all_includes"
 
     AC_TRY_COMPILE([
       #include <tdeversion.h>
@@ -272,7 +272,7 @@ AC_DEFUN([KDE_CHECK_KNS],
     AC_LANG_SAVE
     AC_LANG_CPLUSPLUS
     save_CXXFLAGS="$CXXFLAGS"
-    CXXFLAGS="$KDE_INCLUDES $QT_INCLUDES $all_includes"
+    CXXFLAGS="$KDE_INCLUDES $TQT_INCLUDES $all_includes"
 
     AC_TRY_COMPILE([
       #include <tdeversion.h>