[client] x11: Add inline icon

Many X11 window managers will present an application on their
taskbar as a combination of the application name and an icon
imagery pulled from the X-Property _NET_WM_ICON. Applications
built under frameworks such as Qt or GTK have this property
populated by the framework. This commit adds the Atom _NET_WM_ICON
and populates it with a 64x64 icon of Looking Glass.

client/displayservers/X11/atoms.h

@@ -28,6 +28,7 @@
   DEF_ATOM(_NET_REQUEST_FRAME_EXTENTS, True) \
   DEF_ATOM(_NET_FRAME_EXTENTS, True) \
   DEF_ATOM(_NET_WM_BYPASS_COMPOSITOR, False) \
+  DEF_ATOM(_NET_WM_ICON, True) \
   DEF_ATOM(_NET_WM_STATE, True) \
   DEF_ATOM(_NET_WM_STATE_FULLSCREEN, True) \
   DEF_ATOM(_NET_WM_STATE_FOCUSED, True) \

client/displayservers/X11/x11.c

@@ -23,6 +23,7 @@
 #include "x11.h"
 #include "atoms.h"
 #include "clipboard.h"
+#include "resources/icondata.h"
 
 #include <string.h>
 #include <unistd.h>
@@ -562,6 +563,17 @@ static bool x11Init(const LG_DSInitParams params)
     1
   );
 
+  XChangeProperty(
+    x11.display,
+    x11.window,
+    x11atoms._NET_WM_ICON,
+    XA_CARDINAL,
+    32,
+    PropModeReplace,
+    (unsigned char *)icondata,
+    sizeof(icondata) / sizeof(icondata[0])
+  );
+
   /* create the blank cursor */
   {
     static char data[] = { 0x00 };