build: allow recursive disabling of libraries

build: allow recursive disabling of libraries

Align the code in lib/meson.build with that in drivers/meson.build to
enable recursive disabling of libraries, i.e. if library b depends on
library a, disable library b if a is disabled (either explicitly or
implicitly). This allows libraries to be optional even if other DPDK
libs depend on them, something that was not previously possible.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: David Marchand <david.marchand@redhat.com>