crossgcc: Update makefile builds

- Only build IASL once for the 'all' targets instead of once for each.
- Change the control of what gets built from different targets to
variables on the build line.
- Clean up and correct the list of phony targets
- Don't keep the temporary files around while building all.  This
takes up a lot of space.  If it's desired behavior, add
BUILDGCC_OPTIONS=-t on the make command line.
- Add comments about CPU= and BUILDGCC_OPTIONS= variables
- Add KEEP_SOURCES option

Change-Id: I7752974e249f25717b42be25a841c69af84d5c69
Signed-off-by: Martin Roth <>
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <>
2 files changed