Update libc crate

Cargo.lock

@@ -165,9 +165,9 @@ version = "0.1.0"
 
 [[package]]
 name = "libc"
-version = "0.2.126"
+version = "0.2.139"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "349d5a591cd28b49e1d1037471617a32ddcda5731b99419008085f72d5a53836"
+checksum = "201de327520df007757c1f0adce6e827fe8562fbc28bfd9c15571c66ca1f5f79"
 
 [[package]]
 name = "lock_api"