Handle composite overlay window during drag and drop sessions

* configure.ac: Test for the composite extension and use it if
available.
* msdos/sed1v2.inp: Update.
* src/Makefile.in (XCOMPOSITE_LIBS, XCOMPOSITE_CFLAGS): New
variables.
(EMACS_CFLAGS, LIBES): Add new libs and cflags.
* src/xterm.c (x_dnd_get_target_window): Look for proxy on
composite overlay window if mapped.
(x_term_init): Test if the composite extension is available.
* src/xterm.h (struct x_display_info): New fields for composite
extension presence.

1 files changed, 9 insertions, 0 deletions

diff --git a/src/xterm.h b/src/xterm.h
index 9665e92a9fb..05d5e08dc01 100644
--- a/src/xterm.h
+++ b/src/xterm.h
@@ -429,6 +429,9 @@ struct x_display_info
   /* Atom used in XEmbed client messages.  */
   Atom Xatom_XEMBED, Xatom_XEMBED_INFO;
 
+  /* Atom used to determine whether or not the screen is composited.  */
+  Atom Xatom_NET_WM_CM_Sn;
+
   /* The frame (if any) which has the X window that has keyboard focus.
      Zero if none.  This is examined by Ffocus_frame in xfns.c.  Note
      that a mere EnterNotify event can set this; if you need to know the
@@ -635,6 +638,12 @@ struct x_display_info
 #ifdef HAVE_XINERAMA
   bool xinerama_supported_p;
 #endif
+
+#ifdef HAVE_XCOMPOSITE
+  bool composite_supported_p;
+  int composite_major;
+  int composite_minor;
+#endif
 };
 
 #ifdef HAVE_X_I18N