WITH_NEW_XORG checks broken in some ports

[Antoine Brodin]

Hi there,

It looks like the WITH_NEW_XORG checks are broken in some ports:  it
has to be checked after bsd.port.pre.mk or bsd.port.options.mk has
been included if we want it to be the default for freebsd 11 users.
Affected ports include at least:
- graphics/libEGL
- x11-drivers/xf86-input-synaptics
- graphics/libglesv2
- net/tigervnc

Cheers,

Antoine