This variable $(O) can be used to specify a build directory
when doing an "install" procedure. The default is ".", which
means that targets will be built in the source dpdk.
This option is useful to compile outside of the source tree that may be
read-only.
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Thomas Monjalon <thomas.monjalon@6wind.com>