[pango/pango2-windows: 218/222] pango-hbfontmap-private.h: Use C linkage

[Chun-wei Fan <fanchunwei src gnome org>]

commit 255de34e9d3dac2de1286e714232e7ec74346a96
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Thu Jun 9 10:49:38 2022 +0800

    pango-hbfontmap-private.h: Use C linkage
    
    The DirectWrite support sadly has to be done in C++, so make sure that we use
    C linkage in this private header file so that we can link to
    pango_hb_font_map_repopulate() properly.

 pango/pango-hbfontmap-private.h | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/pango/pango-hbfontmap-private.h b/pango/pango-hbfontmap-private.h
index 6614a147..95148342 100644
--- a/pango/pango-hbfontmap-private.h
+++ b/pango/pango-hbfontmap-private.h
@@ -24,6 +24,8 @@
 #include <pango/pango-fontmap-private.h>
 
 
+G_BEGIN_DECLS
+
 struct _PangoHbFontMap
 {
   PangoFontMap parent_instance;
@@ -56,3 +58,5 @@ struct _PangoHbFontMapClass
 
 void                    pango_hb_font_map_repopulate    (PangoHbFontMap *self,
                                                          gboolean        add_synthetic);
+
+G_END_DECLS