include: dixfontstr.h: drop silent dependency on libxfont2

This header includes libxfont2.h, but the dependency isn't stated anywhere,
causing some drivers to FTBS (when libxont2.h is in non-standard location).

Since this header doesn't seem to need including libxfont2.h at all, just
stop including it, instead of adding yet another dependency to server SDK.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1610>

glamor/glamor_font.c

@@ -20,6 +20,12 @@
  * OF THIS SOFTWARE.
  */
 
+#include <dix-config.h>
+
+#include <stddef.h>
+#include <X11/fonts/fontstruct.h> // libxfont2.h missed to include that
+#include <X11/fonts/libxfont2.h>
+
 #include "glamor_priv.h"
 #include "glamor_font.h"
 #include <dixfontstr.h>

hw/xnest/Font.c

@@ -13,12 +13,14 @@ is" without express or implied warranty.
 */
 #include <dix-config.h>
 
+#include <stddef.h>
 #include <X11/X.h>
 #include <X11/Xatom.h>
 #include <X11/Xdefs.h>
 #include <X11/Xproto.h>
 #include <X11/fonts/font.h>
 #include <X11/fonts/fontstruct.h>
+#include <X11/fonts/libxfont2.h>
 
 #include "misc.h"
 #include "regionstr.h"

hw/xnest/Init.c

@@ -13,10 +13,12 @@ is" without express or implied warranty.
 */
 #include <dix-config.h>
 
+#include <stddef.h>
 #include <X11/X.h>
 #include <X11/Xdefs.h>
 #include <X11/Xproto.h>
 #include <X11/fonts/fontstruct.h>
+#include <X11/fonts/libxfont2.h>
 
 #include "dix/screenint_priv.h"
 #include "miext/extinit_priv.h"

include/dixfontstr.h

@@ -27,7 +27,6 @@ SOFTWARE.
 #include "servermd.h"
 #include "dixfont.h"
 #include <X11/fonts/fontstruct.h>
-#include <X11/fonts/libxfont2.h>
 #include <X11/Xproto.h>         /* for xQueryFontReply */
 
 #define FONTCHARSET(font)	  (font)