pkg/53263: www/geckodriver build error

[mayuresh%acm.org@localhost]

>Number:         53263
>Category:       pkg
>Synopsis:       www/geckodriver build error
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat May 05 18:25:00 +0000 2018
>Originator:     Mayuresh
>Release:        pkgsrc current with last update: Sat May 5 15:41:42 2018 +0000
>Organization:
>Environment:
NetBSD localhost 8.0_RC1 NetBSD 8.0_RC1 (GENERIC.201804191727Z) amd64

>Description:
Build exits with:

   Compiling slog v1.5.2
error[E0277]: the trait bound `*mut core::ops::Fn() + 'static:
core::marker::Sync` is not satisfied in `core::fmt::Arguments<'static>`
   --> /usr/pkgsrc/www/geckodriver/work/vendor/slog-1.5.2/src/ser.rs:228:6
    |
228 | impl SyncSerialize for fmt::Arguments<'static> {}
    |      ^^^^^^^^^^^^^ `*mut core::ops::Fn() + 'static` cannot be shared
between threads safely
    |
    = help: within `core::fmt::Arguments<'static>`, the trait
`core::marker::Sync` is not implemented for `*mut core::ops::Fn() +
'static`
    = note: required because it appears within the type
`core::marker::PhantomData<*mut core::ops::Fn() + 'static>`
    = note: required because it appears within the type `core::fmt::Void`
    = note: required because it appears within the type `&'static
core::fmt::Void`
    = note: required because it appears within the type
`core::fmt::ArgumentV1<'static>`
    = note: required because it appears within the type
`[core::fmt::ArgumentV1<'static>]`
    = note: required because it appears within the type `&'static
[core::fmt::ArgumentV1<'static>]`
    = note: required because it appears within the type
`core::fmt::Arguments<'static>`

error: aborting due to previous error

error: Could not compile `slog`.

>How-To-Repeat:
Build www/geckodriver
>Fix:
This thread suggests that slog dependency can be safely removed without
much loss of functionality.

https://bugzilla.mozilla.org/show_bug.cgi?id=1436830

But what to do is not clear to me.