include: drop closestr.h from public module API

None of the public module API functions use the types defined in here,
this file isn't even included anywhere (in the public headers). Thus it
doesn't seem to be needed in the public API at all - so make it private.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>
Part-of: <https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/1281>
(cherry picked from commit 5b2c00d38a)

hw/xfree86/sdksyms.sh

@@ -231,7 +231,6 @@ cat > sdksyms.c << EOF
 /* include/Makefile.am */
 #include "XIstubs.h"
 #include "Xprintf.h"
-#include "closestr.h"
 #include "closure.h"
 #include "colormap.h"
 #include "colormapst.h"

include/meson.build

@@ -452,7 +452,6 @@ if build_xorg
             'Xprintf.h',
             'callback.h',
             'client.h',
-            'closestr.h',
             'closure.h',
             'colormap.h',
             'colormapst.h',