diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8f083fb..875f3dd 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,70 +1,70 @@
 # The CMake version we require (must be first)
 cmake_minimum_required(VERSION 3.0.2)
 
 project(alkimia VERSION 7.0.80)
 
-option(BUILD_QT4 "Build for Qt4" OFF)
+option(BUILD_QT4 "Build for Qt4" ON)
 
 find_package(ECM 0.0.11 REQUIRED NO_MODULE)
 
 set(CMAKE_MODULE_PATH ${ECM_MODULE_PATH} ${ECM_KDE_MODULE_DIR} ${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules)
 
 include(KDEInstallDirs)
 include(KDECMakeSettings)
 include(KDECompilerSettings NO_POLICY_SCOPE)
 include(FeatureSummary)
 
 # check for PkgConfig, Qt and MPIR/GMP
 find_package(PkgConfig)
 if(BUILD_QT4)
     find_package(Qt4 REQUIRED COMPONENTS QtCore QtGui QtDBus QtTest QtWebKit)
     set(QT_USE_LIBSPREFIX Qt4::Qt)
     set(ALKIMIA_LIB_SUFFIX "")
     set(ALKIMIA_INCLUDE_SUFFIX "Qt4")
     set(ALKIMIA_PATH_SUFFIX)
     set(PC_TARGET_QTPREFIX Qt)
     set(PC_TARGET_SUFFIX)
     set(_kde4_uninstall_rule_created 1)
     find_package(KDE4 REQUIRED)
     include(KDE4Defaults)
     set(KDE_LIBRARIES ${KDE4_KDECORE_LIBS} ${KDE4_KIO_LIBS})
     include_directories(${KDE4_INCLUDES})
 else()
     find_package(Qt5 REQUIRED COMPONENTS Core DBus Test WebKit)
     set(QT_USE_LIBSPREFIX Qt5::)
     set(ALKIMIA_LIB_SUFFIX "5")
     set(ALKIMIA_INCLUDE_SUFFIX "Qt5")
     set(ALKIMIA_PATH_SUFFIX 5)
     set(PC_TARGET_QTPREFIX Qt5)
     set(PC_TARGET_SUFFIX 5)
 endif()
 
 # figure out which multi-precision library to use
 # MPIR is preferred over GMP
 find_package(MPIR)
 if(MPIR_FOUND)
   set(MP_INCLUDE_DIR ${MPIR_INCLUDE_DIR})
   set(MP_LIBRARIES ${MPIR_LIBRARIES})
   set(MP_HEADER mpirxx.h)
   set(MP_CMAKE_MODULE "MPIR")
   set(PC_LIB mpir)
 else()
   find_package(GMP REQUIRED)
   set(MP_INCLUDE_DIR ${GMP_INCLUDE_DIR})
   set(MP_LIBRARIES ${GMP_LIBRARIES})
   set(MP_HEADER gmpxx.h)
   set(MP_CMAKE_MODULE "GMP")
   set(PC_LIB gmp)
 endif()
 
 # check for Doxygen (for API documentation)
 find_package(Doxygen)
 
 feature_summary(WHAT ALL)
 
 add_definitions(-DQT_USE_FAST_CONCATENATION -DQT_USE_FAST_OPERATOR_PLUS)
 include_directories(${MP_INCLUDE_DIR})
 
 add_subdirectory(src)
 add_subdirectory(autotests)
 add_subdirectory(tools)