build xen rc4 with local seabios

 ls -al ./tools/firmware/
total 40
drwxrwxr-x  7 mockbuild mockbuild 4096 Dec 27 16:56 .
drwxrwxr-x 34 mockbuild mockbuild 4096 Dec 27 17:03 ..
drwxrwxr-x  4 mockbuild mockbuild 4096 Dec 27 17:00 etherboot
drwxrwxr-x  3 mockbuild mockbuild 4096 Dec 27 17:01 hvmloader
-rw-rw-r--  1 mockbuild mockbuild 2822 Dec 15 08:35 Makefile
-rw-rw-r--  1 mockbuild mockbuild  470 Dec 15 08:35 ovmf-makefile
drwxrwxr-x  3 mockbuild mockbuild 4096 Dec 27 17:00 rombios
-rw-rw-r--  1 mockbuild mockbuild  400 Dec 15 08:35 Rules.mk
drwxrwxr-x  7 mockbuild mockbuild 4096 Nov  9 21:27 seabios-dir
drwxrwxr-x  2 mockbuild mockbuild 4096 Dec 27 17:00 vgabios