Whenever I use hdldesigner and a core that uses a defines file, When I
go to compile it says "cannot open 'include blah.v" or something like
that. I've had this happen to me before, and my workaround was to
just copy contents of blah.v and replace the include file. But thats
really ugly for this paticular core so I'm trying to find out the proper way
to do this. Thanks in advance.

** Error: C:\hds_projects\ION2/Wishbone_RS232/hdl/uart_rfifo.v(151):
Cannot open `include file "uart_defines.v".

Jamey

Short version: Don't use ISE to compile your files

ISE requires all include files to be correct relative to where you
started it from. So you would need to change every include to:
`include "my/relative/path/include.vh"

Theoretically there's an +incdir type directive so you don't have to
do that, but it's simpler to just create a command-line script and use
XST from the command line.

xst -ifn compile.scr

compile.scr:
run -ifn compile.list -ofn my_design.ngc -top my_design_top
-keep_hierarchy Yes -ofmt NGC -uc my_constraints.xcf -p xc2VP7-FF672-6
-opt_mode Speed -opt_level 2

- Guy