egl: add EGL_platform_device support

This new 'platform' is added by default with no guards.

It is effectively a copy of the surfaceless one, with updated function
names and brand new probe function.

Due to the reuse, some of the ifdef HAVE_SURFACELESS_PLATFORM guards
have been dropped.

A worthy mention are the changes in _egFindDisplay, since the original
and dup'd fd are required, we make use of the plat_opt argument.

Note that no hacks for eglGetDisplay are added - the API works only with
the eglGetPlatformDisplay* API.

v2:
 - s/_eglCompareDeviceDisplay/_eglSameDeviceDisplay/ (Eric)
 - let ^^ return bool (Eric)
 - fixup meson build, move files() further up (Eric)
 - copy from plat. surfaceless w/o the visual cleanups
 - close and free when destroying the dpy
 - sprinkle a few _eglDeviceSupports
 - split fd handling into separate function
 - use directly the render node if no FD is given (Mathias)

v3:
 - s/dpy/disp/g
 - drop swap_buffers* callbacks
 - drop loader_set_logger()
 - drop local define
 - re-introduce _eglGetDRMDeviceRenderNode()
 - EGL_WARN on ForceSoftware with HW device - continue using the HW device
 - bail out for "EGL_MESA_device_software" until it's fixed
 - wire-up the Android build

v4:
 - use new style _eglFindDisplay()
 - split hw vs sw code paths
 - don't close the internal fd (already handled in FiniDisplay())
 - make swrast work (bit hacky bit will do for now)
 - Android for real, drop autotools
 - Correct HW + LIBGL_ALWAYS_SOFTWARE check
 - use the dri2_create_drawable() helper

v5:
 - enhance comment around fd checks (Mathias)
 - rebase for dri2_init_surface() changes

Cc: Mathias Fröhlich <Mathias.Froehlich@gmx.net>
Acked-by: Marek Olšák <marek.olsak@amd.com> (v4)
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>

src/egl/main/egldisplay.h

@@ -50,6 +50,7 @@ enum _egl_platform_type {
    _EGL_PLATFORM_ANDROID,
    _EGL_PLATFORM_HAIKU,
    _EGL_PLATFORM_SURFACELESS,
+   _EGL_PLATFORM_DEVICE,
 
    _EGL_NUM_PLATFORMS,
    _EGL_INVALID_PLATFORM = -1
@@ -149,7 +150,6 @@ struct _egl_extensions
    EGLBoolean WL_create_wayland_buffer_from_image;
 };
 
-
 struct _egl_display
 {
    /* used to link displays */
@@ -168,6 +168,7 @@ struct _egl_display
    struct {
       EGLBoolean ForceSoftware; /**< Use software path only */
       EGLAttrib *Attribs;     /**< Platform-specific options */
+      int fd; /**< plaform device specific, local fd */
    } Options;
 
    /* these fields are set by the driver during init */
@@ -314,6 +315,10 @@ _eglGetSurfacelessDisplay(void *native_display,
                           const EGLAttrib *attrib_list);
 #endif
 
+_EGLDisplay*
+_eglGetDeviceDisplay(void *native_display,
+                     const EGLAttrib *attrib_list);
+
 #ifdef __cplusplus
 }
 #endif