graphics/egl-wayland: unbreak with libglvnd < 1.3.4 after 2aaa5305

In file included from ../src/wayland-thread.c:29:
In file included from ../include/wayland-egldisplay.h:31:
../include/wayland-eglhandle.h:112:9: error: unknown type name 'PFNEGLSTREAMIMAGECONSUMERCONNECTNVPROC'
        PFNEGLSTREAMIMAGECONSUMERCONNECTNVPROC      streamImageConsumerConnect;
        ^
../include/wayland-eglhandle.h:113:9: error: unknown type name 'PFNEGLSTREAMACQUIREIMAGENVPROC'
        PFNEGLSTREAMACQUIREIMAGENVPROC              streamAcquireImage;
        ^
../include/wayland-eglhandle.h:114:9: error: unknown type name 'PFNEGLSTREAMRELEASEIMAGENVPROC'; did you mean 'PFNEGLSTREAMFLUSHNVPROC'?
        PFNEGLSTREAMRELEASEIMAGENVPROC              streamReleaseImage;
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        PFNEGLSTREAMFLUSHNVPROC
/usr/local/include/EGL/eglext.h:1207:34: note: 'PFNEGLSTREAMFLUSHNVPROC' declared here
typedef EGLBoolean (EGLAPIENTRYP PFNEGLSTREAMFLUSHNVPROC) (EGLDisplay dpy, EGLStreamKHR stream);
                                 ^

Reported by:	many