Add support for several Qt flavors

Qt has two flavors: X11 and embedded (QWS). QWS has some limitations
compared to X11. This patch adds an option to select which version to
use.

Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
---
Index: PyQt-x11-gpl-4.11.3/configure-ng.py
===================================================================
--- PyQt-x11-gpl-4.11.3.orig/configure-ng.py
+++ PyQt-x11-gpl-4.11.3/configure-ng.py
@@ -960,6 +960,9 @@ int main(int argc, char **argv)
         if opts.vendlibdir is not None:
             self.vend_lib_dir = opts.vendlibdir
 
+        if opts.qtflavor is not None:
+            self.qt_flavor = opts.qtflavor
+
         # Handle any conflicts.
         if self.qt_shared:
             if len(self.static_plugins) != 0:
@@ -1177,6 +1180,11 @@ def create_optparser(target_config):
             dest="notools",
             help="disable the building of pyuic5, pyrcc5 and pylupdate5 "
                     "[default: enabled]")
+    g.add_option("--qt-flavor", dest='qtflavor', type='string',
+            default="WS_X11", metavar='QTFLAVOR', action='store',
+            help="select Qt flavor beetween WS_X11 and WS_QWS "
+                    "only available on Linux)"
+                    "[default: WS_X11]")
     p.add_option_group(g)
 
     # Vendor ID.
@@ -2088,7 +2096,7 @@ def get_sip_flags(target_config):
     elif target_config.py_platform == 'darwin':
         plattag = 'WS_MACX'
     else:
-        plattag = 'WS_X11'
+        plattag = target_config.qt_flavor
 
     sip_flags.append('-t')
     sip_flags.append(plattag)