This patch distinguishes between the data directory path for GUI and the one
for non-GUI by allowing to set the former path.

highlight package has two outputs: out and gui.  Both outputs have files which
will be in the same directory /share/highlight/ without this patch (see also
install and install-gui tasks in makefile).  In the gui's data directory,
there are GUI specific files in /share/highlight/gui-files/{l10n,ext}/.

diff --git a/src/gui-qt/main.cpp b/src/gui-qt/main.cpp
index 4700dc1..3567745 100644
--- a/src/gui-qt/main.cpp
+++ b/src/gui-qt/main.cpp
@@ -47,8 +47,8 @@ int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);
     QTranslator translator;
-#ifdef DATA_DIR
-    translator.load(QString("%1/gui_files/l10n/highlight_%2").arg(DATA_DIR).arg(QLocale::system().name()));
+#ifdef GUI_DATA_DIR
+    translator.load(QString("%1/gui_files/l10n/highlight_%2").arg(GUI_DATA_DIR).arg(QLocale::system().name()));
 #else
     translator.load(QString("%1/gui_files/l10n/highlight_%2").arg(QDir::currentPath()).arg(QLocale::system().name()));
 #endif
diff --git a/src/gui-qt/mainwindow.cpp b/src/gui-qt/mainwindow.cpp
index 3a21ad2..f060431 100644
--- a/src/gui-qt/mainwindow.cpp
+++ b/src/gui-qt/mainwindow.cpp
@@ -2131,8 +2131,8 @@ QString MainWindow::getDistFileFilterPath(){
 #ifdef Q_OS_OSX
     return QCoreApplication::applicationDirPath()+"/../Resources/gui_files/ext/fileopenfilter.conf";
 #else
-    #ifdef DATA_DIR
-    return QString(DATA_DIR) + "/gui_files/ext/fileopenfilter.conf";
+    #ifdef GUI_DATA_DIR
+    return QString(GUI_DATA_DIR) + "/gui_files/ext/fileopenfilter.conf";
     #else
     return QDir::currentPath()+"/gui_files/ext/fileopenfilter.conf";
     #endif
diff --git a/src/makefile b/src/makefile
index b1d7988..2963105 100644
--- a/src/makefile
+++ b/src/makefile
@@ -118,7 +118,7 @@ gui-qt: highlight-gui
 
 highlight-gui: libhighlight.a ${GUI_OBJECTS}
 	cd gui-qt && \
-	${QMAKE} 'DEFINES+=DATA_DIR=\\\"${HL_DATA_DIR}\\\" CONFIG_DIR=\\\"${HL_CONFIG_DIR}\\\" DOC_DIR=\\\"${HL_DOC_DIR}\\\" ' && \
+	${QMAKE} 'DEFINES+=DATA_DIR=\\\"${HL_DATA_DIR}\\\" CONFIG_DIR=\\\"${HL_CONFIG_DIR}\\\" DOC_DIR=\\\"${HL_DOC_DIR}\\\" GUI_DATA_DIR=\\\"${GUI_DATA_DIR}\\\" ' && \
 	$(MAKE)
 
 $(OBJECTFILES) : makefile