Added a build system option to enable/disable uitools support as some distributions do not support that

src/pymod/QtUiTools/QtUiTools.pro

@@ -8,7 +8,7 @@ SOURCES = \
 
 HEADERS += \
 
-contains(QT_MODULES, uitools) {
+equals(HAVE_QT_UITOOLS, "1") {
   LIBS += -lklayout_QtUiTools 
 }
 

src/pymod/pymod.pro

@@ -1,4 +1,6 @@
 
+include($$PWD/../klayout.pri)
+
 TEMPLATE = subdirs
 SUBDIRS = \
   db \
@@ -20,7 +22,6 @@ SUBDIRS = \
         QtSql \
         QtWidgets \
         QtDesigner \
-        QtUiTools \
         QtMultimedia \
         QtPrintSupport \
         QtSvg \
@@ -35,13 +36,16 @@ SUBDIRS = \
         QtXml \
         QtSql \
         QtNetwork \
-        QtDesigner \
-        QtUiTools
+        QtDesigner
 
     }
   }
 }
 
+equals(HAVE_QT_UITOOLS, "1") {
+  SUBDIRS += QtUiTools
+}
+
 ALL_DIRS = $$SUBDIRS
 
 SUBDIRS += unit_tests