net-p2p/intermodal: fix build on powerpc

error[E0412]: cannot find type c_long in the crate root

--> /wrkdirs/usr/ports/net-p2p/intermodal/work/intermodal-0.1.13/cargo-crates/libc-0.2.78/src/unix/bsd/freebsdlike/freebsd/freebsd11/mod.rs:214:19
 |

214 | msgtyp: ::c_long,

|                   ^^^^^^ not found in the crate root
|

help: consider importing this type alias

|

4 + use ffi::c_long;

|

help: if you import c_long, refer to it directly

|

214 - msgtyp: ::c_long,
214 + msgtyp: c_long,