gtk-3 missing symbol on 9.0-RC

[Mike Pumford <mpumford%mudcovered.org.uk@localhost>]

I use native X11 on 9.0-RC1 amd64 and after my latest pkgsrc build I'm 
getting:
/usr/pkg/lib/libgtk-3.so.0: Undefined symbol "epoxy_eglInitialize" 
(symnum = 1372)

Looking at the built-in libepoxy that symbol does exist so clearly the 
built in MesaLib has EGL support.

However the pkgsrc libepoxy isn't picking that up as 
MESALIB_SUPPORTS_EGL is not set to yes. I'm going to try a build with 
that explicitly defined to see if that fixes things. I'm guessing this 
is something that x11-links should be doing for 9.0-RC1

Mike