Fix cross-reference filename/line number. We were reporting (wrongly) the

Fix cross-reference filename/line number.  We were reporting (wrongly) the
virtual line number rather than the physical filename/line number.  This
was broken when the errwarn code was changed and not caught because I didn't
check the errwarn results closely enough for this case.

* nasm-token.re, gas-token.re: Propagate warnings from arch early.
This is a case where we probably want the double-error/warning on a single
line.

* errwarn.h: Add xref filename to yasm_print_error_func, and document all
parameters.
* errwarn.c: Get the physical file/line for xref virtual line.
* yasm.c: Update to match new yasm_print_error_func definition.

* pushf-err.errwarn: Correct test.

svn path=/trunk/yasm/; revision=1556