Fix ECM to use qmake instead of hardcoding plugin install dirs

Packagers and other interested folks should pass -DKDE_INSTALL_USE_QT_SYS_PATHS=ON
when building in order to install various files to the same dir as the Qt5 install
dirs.

CCMAIL: kde-packagers@kde.org

REVIEW: 119901

3 files changed, 49 insertions, 16 deletions

diff --git a/kde-modules/KDEInstallDirs.cmake b/kde-modules/KDEInstallDirs.cmake
index 880539b7..54eb49cc 100644
--- a/kde-modules/KDEInstallDirs.cmake
+++ b/kde-modules/KDEInstallDirs.cmake
@@ -162,11 +162,6 @@
 # (To distribute this file outside of extra-cmake-modules, substitute the full
 #  License text for the above reference.)
 
-
-# TODO:
-# - Try to figure out proper Qt-related dirs when installing to the same
-#   prefix as Qt (look for qtpaths)
-
 # Figure out what the default install directory for libraries should be.
 # This is based on the logic in GNUInstallDirs, but simplified (the
 # GNUInstallDirs code deals with re-configuring, but that is dealt with
@@ -199,7 +194,6 @@ if((CMAKE_SYSTEM_NAME MATCHES "Linux|kFreeBSD" OR CMAKE_SYSTEM_NAME STREQUAL "GN
   endif()
 endif()
 
-
 # Macro for variables that are relative to another variable. We store an empty
 # value in the cache (for documentation/GUI cache editor purposes), and store
 # the default value in a local variable. If the cache variable is ever set to
@@ -287,7 +281,6 @@ macro(_define_absolute varname dir docstring)
     _define_relative("${varname}" "" "${dir}" "${docstring}" ${ARGN})
 endmacro()
 
-
 if(APPLE)
     _define_absolute(BUNDLEDIR "/Applications/KDE"
         "application bundles"
@@ -328,22 +321,41 @@ _define_relative(CMAKEPACKAGEDIR LIBDIR "cmake"
     "CMake packages, including config files"
     CMAKECONFIG_INSTALL_PREFIX)
 
+option (KDE_INSTALL_USE_QT_SYS_PATHS "Install mkspecs files, Plugins and Imports to the Qt 5 install dir")
+if(KDE_INSTALL_USE_QT_SYS_PATHS)
 # Qt-specific vars
-_define_relative(QTPLUGINDIR LIBDIR "plugins"
-    "Qt plugins"
-    QT_PLUGIN_INSTALL_DIR)
+    include(ECMQueryQmake)
+
+    query_qmake(qt_plugins_dir QT_INSTALL_PLUGINS)
+
+    _define_absolute(QTPLUGINDIR ${qt_plugins_dir}
+        "Qt plugins"
+         QT_PLUGIN_INSTALL_DIR)
+
+    query_qmake(qt_imports_dir QT_INSTALL_IMPORTS)
+
+    _define_absolute(QTQUICKIMPORTSDIR QTPLUGINDIR ${qt_imports_dir}
+        "QtQuick1 imports"
+        IMPORTS_INSTALL_DIR)
+
+else()
+    _define_relative(QTPLUGINDIR LIBDIR "plugins"
+        "Qt plugins"
+        QT_PLUGIN_INSTALL_DIR)
+
+    _define_relative(QTQUICKIMPORTSDIR QTPLUGINDIR "imports"
+        "QtQuick1 imports"
+        IMPORTS_INSTALL_DIR)
+endif()
+
 _define_relative(PLUGINDIR QTPLUGINDIR ""
     "Plugins"
     PLUGIN_INSTALL_DIR)
-_define_relative(QTQUICKIMPORTSDIR QTPLUGINDIR "imports"
-    "QtQuick1 imports"
-    IMPORTS_INSTALL_DIR)
+
 _define_relative(QMLDIR LIBDIR "qml"
     "QtQuick2 imports"
     QML_INSTALL_DIR)
 
-
-
 _define_absolute(INCLUDEDIR "include"
     "C and C++ header files"
     INCLUDE_INSTALL_DIR)
diff --git a/modules/ECMGeneratePriFile.cmake b/modules/ECMGeneratePriFile.cmake
index 34001d6c..53cd69db 100644
--- a/modules/ECMGeneratePriFile.cmake
+++ b/modules/ECMGeneratePriFile.cmake
@@ -82,7 +82,13 @@
 # (To distribute this file outside of extra-cmake-modules, substitute the full
 #  License text for the above reference.)
 
-set(ECM_MKSPECS_INSTALL_DIR mkspecs/modules CACHE PATH "The directory where mkspecs will be installed to.")
+if(KDE_ECM_INSTALL_TO_QT_SYS_DIR)
+  include(ECMQueryQmake)
+  query_qmake(qt_host_data_dir QT_HOST_DATA)
+  set(ECM_MKSPECS_INSTALL_DIR ${qt_host_data_dir}/mkspecs/modules CACHE PATH "The directory where mkspecs will be installed to.")
+else ()
+  set(ECM_MKSPECS_INSTALL_DIR mkspecs/modules CACHE PATH "The directory where mkspecs will be installed to.")
+endif()
 
 function(ECM_GENERATE_PRI_FILE)
   set(options )
diff --git a/modules/ECMQueryQmake.cmake b/modules/ECMQueryQmake.cmake
new file mode 100644
index 00000000..5147fcc7
--- /dev/null
+++ b/modules/ECMQueryQmake.cmake
@@ -0,0 +1,15 @@
+find_package(Qt5Core QUIET)
+
+if (TARGET Qt5::qmake)
+  get_target_property(QMAKE_EXECUTABLE Qt5::qmake LOCATION)
+else()
+  set(QMAKE_EXECUTABLE "qmake-qt5" CACHE)
+endif()
+
+function(QUERY_QMAKE RESULT VAR)
+    exec_program(${QMAKE_EXECUTABLE} ARGS "-query ${VAR}" RETURN_VALUE return_code OUTPUT_VARIABLE output )
+    if(NOT return_code)
+        file(TO_CMAKE_PATH "${output}" output)
+        set(${RESULT} ${output} PARENT_SCOPE)
+    endif()
+endfunction(QUERY_QMAKE)