This updates the following third-party dependencies of mozjs_sys:
gcc v0.3.40 -> v0.3.42
libc v0.2.18 -> v0.2.20
libz-sys v1.0.10 -> v1.0.12
pkg-config v0.3.8 -> v0.3.9
Since libc is updated, we also need to update the gkrust lockfiles to use the
new version, because leaving it at 0.2.18 will result in improper vendoring of
the crates (see bug 1336528). None of the other mozjs_sys crates are shared by
gkrust.
MozReview-Commit-ID: 5FHELF8YKD0
--HG--
extra : rebase_source : a6a4d635d4a3b9c2faa23f935c4be59e8588fbbf
Kartikaya Gupta
Nick Fitzgerald