SPEC reference design doesn't work on standalone SPEC

Peter Jansweijer reports:
The Genum chip is not initialized and keeps asserting signal "gn_rst_n" hence the SPEC never leaves the reset state.
This signal is asynchronously or-ed with button_1 so this button is not working either.

It seems that with the new resetting scheme of the v4.0 we've connected the level-sensitive reset signal (gennum rst or'ed with a button) directly to the system clock pll (in xwrc_platform_xilinx.vhd). Thus, the system clock pll is held in reset all the time when Genum is not initialized.