Change in coreboot[master]: Makefile: Add $(xcompile) to specify where to write xcompile

[Raul Rangel (Code Review)]

Hello build bot (Jenkins), Nico Huber, Patrick Georgi, Martin Roth, Stefan Reinauer, Paul Menzel, Julius Werner,

I'd like you to reexamine a change. Please visit

https://review.coreboot.org/c/coreboot/+/28101

to look at the new patch set (#11).

Change subject: Makefile: Add $(xcompile) to specify where to write xcompile
......................................................................

Makefile: Add $(xcompile) to specify where to write xcompile

This file was being written to the root src directory. It is the only
file being written to src during a normal build, while all others are
being written to $(obj). I added a new variable to allow specifying the
xcompile path. This allows generating a single file if building multiple
boards. I also moved the default location into $(obj) so we don't
pollute the src directory by default.

I also cleaned up the generation of xcompile by removing the unnecessary
eval and NOCOMPILE check.

I also left .xcompile in distclean so it cleans up stale files.

Since .xcompile is written into $(obj), `make clean` will now remove it.

The tegra Makefiles are outside of the normal build process, so I just
updated those Makefiles to point to the default xcompile location of a
normal build. The what-jenkins-does target had to be updated to support
these special targets. We generate an xcompile specifically for these
targets and pass it into the Makefile. Ideally we should get these
targets added to the main build.

BUG=b:112267918
TEST=ran `emerge-grunt coreboot` and `make what-jenkins-does`

Signed-off-by: Raul E Rangel 
Change-Id: Ia83f234447b977efa824751c9674154b77d606b0
---
M Makefile
M Makefile.inc
M src/soc/nvidia/tegra124/lp0/Makefile
M src/soc/nvidia/tegra210/lp0/Makefile
M util/abuild/abuild
M util/crossgcc/Makefile.inc
M util/docker/Makefile
M util/testing/Makefile.inc
8 files changed, 29 insertions(+), 20 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/01/28101/11