diff --git a/Krusader.tdevelop b/Krusader.tdevelop
index b546fa1..e83a0c2 100644
--- a/Krusader.tdevelop
+++ b/Krusader.tdevelop
@@ -50,16 +50,16 @@
         <configargs/>
         <builddir/>
         <topsourcedir/>
-        <cppflags>-DQT_THREAD_SUPPORT</cppflags>
+        <cppflags>-DTQT_THREAD_SUPPORT</cppflags>
         <ldflags/>
         <ccompiler>kdevgccoptions</ccompiler>
         <cxxcompiler>kdevgppoptions</cxxcompiler>
         <f77compiler>kdevpgf77options</f77compiler>
         <ccompilerbinary/>
-        <cxxcompilerbinary>-DQT_THREAD_SUPPORT</cxxcompilerbinary>
+        <cxxcompilerbinary>-DTQT_THREAD_SUPPORT</cxxcompilerbinary>
         <f77compilerbinary/>
         <cflags/>
-        <cxxflags>-DQT_THREAD_SUPPORT </cxxflags>
+        <cxxflags>-DTQT_THREAD_SUPPORT </cxxflags>
         <f77flags/>
         <envvars/>
       </default>
diff --git a/acinclude.m4 b/acinclude.m4
index bbbb70c..c2a6b6b 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -1333,7 +1333,7 @@ KDE_MT_LIBS=
 if test "x$kde_use_qt_mt" = "xyes"; then
   KDE_CHECK_THREADING
   if test "x$kde_use_threading" = "xyes"; then
-    CPPFLAGS="$USE_THREADS -DQT_THREAD_SUPPORT $CPPFLAGS"
+    CPPFLAGS="$USE_THREADS -DTQT_THREAD_SUPPORT $CPPFLAGS"
     KDE_MT_LDFLAGS="$USE_THREADS"
     KDE_MT_LIBS="$LIBPTHREAD"
   else