egl: add base EGL_EXT_device_base implementation

Introduce the API for device query and enumeration. Those at the moment
produce nothing useful since zero devices are actually available.

That contradicts with the spec, so the extension isn't advertised just
yet.

With later commits we'll add support for software (always) and hardware
devices. Each one exposing the respective extension string.

v2:
 - fold API boilerplate into this patch
 - move _eglAddDevice, _eglDeviceSupports, _eglRefreshDeviceList to this
patch (Eric, Mathias)
 - make _eglFiniDevice the one called last

v3:
 - comment on the dummy _egl_device_extension enum entry (Eric)
 - annotate dev as MAYBE_UNUSED (Mathias)

Signed-off-by: Emil Velikov <[email protected]>
Reviewed-by: Mathias Fröhlich <[email protected]>

1 files changed, 2 insertions, 0 deletions

diff --git a/src/egl/main/eglglobals.h b/src/egl/main/eglglobals.h
index 6655ccab65c..63bea4ebc38 100644
--- a/src/egl/main/eglglobals.h
+++ b/src/egl/main/eglglobals.h
@@ -54,6 +54,8 @@ struct _egl_global
    /* the list of all displays */
    _EGLDisplay *DisplayList;
 
+   _EGLDevice *DeviceList;
+
    EGLint NumAtExitCalls;
    void (*AtExitCalls[10])(void);