A recent change to net/net-snmp by rillig@ adds a dependency on
shells/bash. Darwin/MacOSX already has /bin/bash (v2.05), so I don't
think this change is necessary for Darwin/MacOSX (unless there is
something here that really requires bash v3.1).

I tried setting USE_BUILTIN.bash=yes, but building net-snmp still wants
to build shells/bash. Perhaps the dependency should be conditional on
${OPSYS} or ${MACHINE_PLATFORM} ?

Thanks,
Mark