tests/vm: expose BUILD_TARGET, TARGET_LIST and EXTRA_CONFIGURE_OPTS
Now the underlying basevm support passes these along we can expose
some additional variables to our Makefile to allow more customised
tweaking of the build. For example:
make vm-build-freebsd TARGET_LIST=aarch64-softmmu \
EXTRA_CONFIGURE_OPTS="--disable-tools --disable-docs" \
BUILD_TARGET=check-softfloat
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>