diff --git a/m4/qt.m4 b/m4/qt.m4
index 1afd50d..8e5a557 100644
--- a/m4/qt.m4
+++ b/m4/qt.m4
@@ -1,102 +1,102 @@
 dnl qt.m4
 dnl Copyright (C) 2015 Intevation GmbH
 dnl
 dnl This file is part of PINENTRY.
 dnl
 dnl PINENTRY is free software; you can redistribute it and/or modify
 dnl it under the terms of the GNU General Public License as published by
 dnl the Free Software Foundation; either version 2 of the License, or
 dnl (at your option) any later version.
 dnl
 dnl PINENTRY is distributed in the hope that it will be useful,
 dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
 dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 dnl GNU General Public License for more details.
 dnl
 dnl You should have received a copy of the GNU General Public License
 dnl along with this program; if not, write to the Free Software
 dnl Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
 
 dnl Autoconf macro to find either Qt4 or Qt5
 dnl
 dnl sets PINENTRY_QT_LIBS and PINENTRY_QT_CFLAGS
 dnl
 dnl if QT5 was found have_qt5_libs is set to yes
 dnl if QT4 was found have_qt4_libs is set to yes
 dnl
 dnl The moc lookup code is based on libpoppler (rev. d821207)
 
 AC_DEFUN([FIND_QT],
 [
   AC_ARG_ENABLE(pinentry-qt5,
                 AC_HELP_STRING([--disable-pinentry-qt5],
                            [Don't use qt5 even if it is available.]),
                 enable_pinentry_qt5=$enableval,
                 enable_pinentry_qt5="try")
 
-  have_qt5_libs = "no";
+  have_qt5_libs="no";
 
   if test "$enable_pinentry_qt5" != "no"; then
     PKG_CHECK_MODULES(PINENTRY_QT,
                       Qt5Core >= 5.0.0 Qt5Gui >= 5.0.0 Qt5Widgets >= 5.0.0,
                       [have_qt5_libs="yes"],
                       [have_qt5_libs="no"])
 
     if "$PKG_CONFIG" --variable qt_config Qt5Core | grep -q "reduce_relocations"; then
       PINENTRY_QT_CFLAGS="$PINENTRY_QT_CFLAGS -fpic"
     fi
   fi
   if test "$have_qt5_libs" = "yes"; then
     AC_CHECK_TOOL(MOC, moc)
     AC_MSG_CHECKING([moc version])
     mocversion=`$MOC -v 2>&1`
     mocversiongrep=`echo $mocversion | grep "Qt 5\|moc 5"`
     if test x"$mocversiongrep" != x"$mocversion"; then
       AC_MSG_RESULT([no])
       # moc was not the qt5 one, try with moc-qt5
       AC_CHECK_TOOL(MOC2, moc-qt5)
       mocversion=`$MOC2 -v 2>&1`
       mocversiongrep=`echo $mocversion | grep "Qt 5\|moc-qt5 5\|moc 5"`
       if test x"$mocversiongrep" != x"$mocversion"; then
         AC_CHECK_TOOL(QTCHOOSER, qtchooser)
         qt5tooldir=`QT_SELECT=qt5 qtchooser -print-env | grep QTTOOLDIR | cut -d '=' -f 2 | cut -d \" -f 2`
         mocversion=`$qt5tooldir/moc -v 2>&1`
         mocversiongrep=`echo $mocversion | grep "Qt 5\|moc 5"`
         if test x"$mocversiongrep" != x"$mocversion"; then
           # no valid moc found
           have_qt5_libs="no";
         else
           MOC=$qt5tooldir/moc
         fi
       else
         MOC=$MOC2
       fi
     fi
   fi
   if test "$have_qt5_libs" != "yes"; then
     PKG_CHECK_MODULES(PINENTRY_QT,
                       QtCore >= 4.4.0 QtGui >= 4.4.0,
                       [have_qt4_libs="yes"],
                       [have_qt4_libs="no"])
     if test "$have_qt4_libs" = "yes"; then
       AC_CHECK_TOOL(MOC, moc)
       AC_MSG_CHECKING([moc version])
       mocversion=`$MOC -v 2>&1`
       mocversiongrep=`echo $mocversion | grep "Qt 4"`
       if test x"$mocversiongrep" != x"$mocversion"; then
         AC_MSG_RESULT([no])
         # moc was not the qt4 one, try with moc-qt4
         AC_CHECK_TOOL(MOC2, moc-qt4)
         mocversion=`$MOC2 -v 2>&1`
         mocversiongrep=`echo $mocversion | grep "Qt 4"`
         if test x"$mocversiongrep" != x"$mocversion"; then
           # no valid moc found
           have_qt4_libs="no";
           MOC="not found"
         else
           MOC=$MOC2
         fi
       fi
     fi
   fi
 ])