The top build system sets up HOSTCFLAGS a bit and exports it, but other
places use HOST_CFLAGS instead. Unify the two as HOSTCFLAGS so that the
values stay in sync.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Modifications are based on the linux kernel approach and
support two use cases:
1) Add O= to the make command line
'make O=/tmp/build all'
2) Set environement variable BUILD_DIR to point to the desired location
'export BUILD_DIR=/tmp/build'
'make'
The second approach can also be used with a MAKEALL script
'export BUILD_DIR=/tmp/build'
'./MAKEALL'
Command line 'O=' setting overrides BUILD_DIR environent variable.
When none of the above methods is used the local build is performed and
the object files are placed in the source directory.
