qemu fails on NetBDS 8 amd64

[Greg Troxel <gdt%lexort.com@localhost>]

base xsrc, pkgsrc head, up to date.

I had a successful build on May 22.


  CC      ui/egl-helpers.o
In file included from /tmp/work/emulators/qemu/work/.buildlink/include/epoxy/egl.h:46:0,
                 from /tmp/work/emulators/qemu/work/qemu-5.0.0/include/ui/egl-helpers.h:5,
                 from ui/egl-helpers.c:21:
/tmp/work/emulators/qemu/work/.buildlink/include/epoxy/egl_generated.h:10:29: fatal error: EGL/eglplatform.h: No such file or directory
compilation terminated.
gmake: *** [/tmp/work/emulators/qemu/work/qemu-5.0.0/rules.mak:69: ui/egl-helpers.o] Error 1