Use native fonts on win32 instead of FontConfig (bgo#785313)

The version 1.34 selected as pangocairo_requirement is the first version
with PangoCairo.FontMap.set_default behaviour identical to the version
Pango 1.40 which was used for testing.
It maybe works with previous versions too, but they are ancient.

Code assumes that version requirement is satisfied if import of both
Gtk and PangoCairo succeeds since Gtk 3.14 depends on Pango 1.36

Author: Vasily Galkin

bin/meld

@@ -173,6 +173,7 @@ def check_requirements():
     gtk_requirement = (3, 14)
     glib_requirement = (2, 36, 0)
     gtksourceview_requirement = (3, 14, 0)
+    pangocairo_requirement = (1, 34)
 
     def missing_reqs(mod, ver, exception=None):
         if isinstance(exception, ImportError):
@@ -209,6 +210,13 @@ def check_requirements():
     except (ImportError, AssertionError) as e:
         missing_reqs("GtkSourceView", gtksourceview_requirement, e)
 
+    try:
+        gi.require_version("PangoCairo", "1.0")
+        from gi.repository import PangoCairo
+        # Only check that imports ok; the version is fine since Gtk loaded fine
+    except (ImportError, ValueError) as e:
+        missing_reqs("PangoCairo", pangocairo_requirement, e)
+
 
 def setup_resources():
     from gi.repository import GLib
@@ -347,5 +355,10 @@ if __name__ == '__main__':
         from gi.repository import GLib
         GLib.unix_signal_add(GLib.PRIORITY_DEFAULT, signal.SIGINT,
                              lambda *args: meld.meldapp.app.quit(), None)
+    if sys.platform == 'win32':
+        # FontConfig on win32 at least with version <= 2.12.6 can cause several
+        # minutes 'hang' during first startup. So use native fonts backend.
+        from gi.repository import PangoCairo
+        PangoCairo.FontMap.set_default(PangoCairo.Win32FontMap()) 
     status = meld.meldapp.app.run(sys.argv)
     sys.exit(status)