Changes

build: glx: Lower gl version to work with libglvnd

When using mesa with libglvnd support, mesa will no longer install the
gl, glx, egl pkg-config files but instead let libglvnd provide them.
libglvnd maintainers decided to change the versioning as it was
mesa-specific previously. Now the libraries have versions of the API
they expose[1].
This causes problems when building the X server:

  checking for glproto >= 1.4.17 gl >= 9.2.0... no
  configure: error: Package requirements (glproto >= 1.4.17 gl >= 9.2.0) were not met:

  Requested 'gl >= 9.2.0' but version of gl is 1.2

Lower the version requirement to 1.2 to allow building against libglvnd
provided libraries

[1] https://github.com/NVIDIA/libglvnd/commit/0dfaea2bcb7cdcc785f95e244223bd004a2d7fba

(cherry picked from commit e6ef2b12404dfec7f23592a3524d2a63d9d25802)

meson: Fix another reference to "gl" 9.2.0

Previous commit e6ef2b12 missed a spot.

(cherry picked from commit c7486613b0dc586f93f6ba293d9b55c69995b05c)

glamor/xwayland: Define EGL_NO_X11

Define EGL_NO_X11 everywhere were we also define MESA_EGL_NO_X11_HEADERS,
EGL_NO_X11 is the MESA_EGL_NO_X11_HEADERS equivalent for the egl headers
shipped with libglvnd.

This fixes the xserver not building with the libglvnd-1.2.0 headers:

In file included from /usr/include/EGL/eglplatform.h:128,
                 from /usr/include/epoxy/egl_generated.h:11,
                 from /usr/include/epoxy/egl.h:46,
                 from glamor_priv.h:43,
                 from glamor_composite_glyphs.c:25:
/usr/include/X11/Xlib.h:222:2: error: conflicting types for 'GC'
  222 | *GC;
      |  ^~
In file included from glamor.h:34,
                 from glamor_priv.h:32,
                 from glamor_composite_glyphs.c:25:
../include/gcstruct.h:282:3: note: previous declaration of 'GC' was here
  282 | } GC;
      |   ^~

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
(cherry picked from commit 741bd73429e337071f49509ddcc5fb392e20b0f6)

WIP: Fix XRecord to handle ButtonPress events from touchscreens

See:

* https://gitlab.freedesktop.org/xorg/xserver/-/issues/1046
* https://lists.x.org/archives/xorg-devel/2020-July/058582.html

debian/changelog: bump for 1.20.4.1

debian/control: add mesa-common-dev

debian/control: add libx11-xcb-dev

debian/control: remove udeb

debian/rules: more udeb removal