diff --git a/acinclude.m4.in b/acinclude.m4.in
index 1e6261a..5ad0e76 100644
--- a/acinclude.m4.in
+++ b/acinclude.m4.in
@@ -1154,6 +1154,7 @@ fi
 if test "$kde_qtver" = "3"; then
 if $PKG_CONFIG --exists qt-mt ; then
 cat >> conftest.$ac_ext <<EOF
+#include <tqt.h>
 #include <qglobal.h>
 #include <qapplication.h>
 EOF
@@ -1671,7 +1672,7 @@ else
 fi
 
 AC_FIND_FILE($kde_qt_header, $qt_incdirs, qt_incdir)
-if test -n "$qt_incdir"; then
+if test "$qt_incdir" = "NO"; then
    AC_FIND_FILE($kde_tqt_header, $qt_incdirs, qt_incdir)
 fi
 ac_qt_includes="$qt_incdir"
@@ -3828,6 +3829,7 @@ if test "$kde_qtver" = "3"; then
 if $PKG_CONFIG --exists qt-mt ; then
           AC_TRY_COMPILE(
           [
+#include <tqt.h>
 #include <qglobal.h>
 #if Q_EXPORT - 0 != 0
 /* if this compiles, then Q_EXPORT is undefined */