arch/x86/ Pass $(AS) and $(CPP) to SeaBIOS

SeaBIOS’ Makefile requires cpp (C Preprocessor) to build. Modify
the xcompile script to search for cpp program path, and pass it to
SeaBIOS’ ``. Also pass the program path for as (GNU assembler).

This is needed, so the crossgcc toolchain to build the SeaBIOS payload
under Mac OSX. OSX ships a cpp program, but it works differently
from GNU CPP, so we need to override it.

Change-Id: If996ffbb76ec4bd16079b54b41f3fac07bfe25be
Signed-off-by: Andrew Wu <>
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <>
Reviewed-by: Jonathan A. Kollasch <>
3 files changed