package/x11r7/xserver_xorg-server: fix arm glibc-2.30 compile

Fixes:

  In file included from lnx_init.c:33:
  ../../../../hw/xfree86/common/compiler.h:767:10: fatal error: sys/io.h: No such file or directory
   #include <sys/io.h>
          ^~~~~~~~~~
  compilation terminated.

The ARM sys/io.h has been removed from upstream glibc, which is in
buildroot. This causes the xorg-server build to fail on ARM when using
the glibc toolchain. See [1], [2].

The following patches ([3], [4]) from upstream xserver fix this, but
have not yet been released.

[1] https://sourceware.org/glibc/wiki/Release/2.30#A.3Csys.2BAC8-io.h.3E_removed_on_32-bit_Arm
[2] https://gitlab.freedesktop.org/xorg/xserver/issues/840
[3] https://gitlab.freedesktop.org/xorg/xserver/commit/6a2ce6c5da9456b97683db6224f38ef3b02cce4b
[4] https://gitlab.freedesktop.org/xorg/xserver/commit/fe4cd0e7f5c58fa94db36326aadc1bd4e6d73eba



Signed-off-by: Thomas Preston <thomas.preston@codethink.co.uk>
Reviewed-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>