Building for production...
~/src/toolbox/.build/checkouts/swift-log/Sources/Logging/Logging.swift:1392:64: error: value of optional type 'UnsafeMutablePointer<tm>?' must be unwrapped to a value of type 'UnsafeMutablePointer<tm>'
        strftime(&buffer, buffer.count, "%Y-%m-%dT%H:%M:%S%z", localTime)
                                                               ^
~/src/toolbox/.build/checkouts/swift-log/Sources/Logging/Logging.swift:1391:13: note: short-circuit using 'guard' to exit this function early if the optional value contains 'nil'
        let localTime = localtime(&timestamp)
            ^
        guard                                 else { return <#default value#> }
~/src/toolbox/.build/checkouts/swift-log/Sources/Logging/Logging.swift:1391:25: note: coalesce using '??' to provide a default when the optional value contains 'nil'
        let localTime = localtime(&timestamp)
                        ^
                                              ?? <#default value#>
~/src/toolbox/.build/checkouts/swift-log/Sources/Logging/Logging.swift:1391:25: note: force-unwrap using '!' to abort execution if the optional value contains 'nil'
        let localTime = localtime(&timestamp)
                        ^
                                             !
~/src/toolbox/.build/checkouts/swift-log/Sources/Logging/Logging.swift:1392:64: note: coalesce using '??' to provide a default when the optional value contains 'nil'
        strftime(&buffer, buffer.count, "%Y-%m-%dT%H:%M:%S%z", localTime)
                                                               ^
                                                                         ?? <#default value#>
~/src/toolbox/.build/checkouts/swift-log/Sources/Logging/Logging.swift:1392:64: note: force-unwrap using '!' to abort execution if the optional value contains 'nil'
        strftime(&buffer, buffer.count, "%Y-%m-%dT%H:%M:%S%z", localTime)
                                                               ^
                                                                        !
error: fatalError
[12/22] Compiling c-atomics.c
Swift/ErrorType.swift:200: Fatal error: Error raised at top level: build.ShellError(terminationStatus: 1)
Current stack trace:
0    libswiftCore.so                    0x00007fa53dc986d0 _swift_stdlib_reportFatalErrorInFile + 109
1    libswiftCore.so                    0x00007fa53d964d85 <unavailable> + 1461637
2    libswiftCore.so                    0x00007fa53d964ba7 <unavailable> + 1461159
3    libswiftCore.so                    0x00007fa53d963b10 _assertionFailure(_:_:file:line:flags:) + 342
4    libswiftCore.so                    0x00007fa53d9cac5c <unavailable> + 1879132
5    build                              0x00005611330b8177 <unavailable> + 8567
6    libc.so.6                          0x00007fa53c827cd0 <unavailable> + 163024
7    libc.so.6                          0x00007fa53c827d00 __libc_start_main + 138
8    build                              0x00005611330b7e65 <unavailable> + 7781

💣 Program crashed: Illegal instruction at 0x00007fa53d963c72

Thread 0 "build" crashed:

0 0x00007fa53d963c72 _assertionFailure(_:_:file:line:flags:) + 354 in libswiftCore.so
1 0x00007fa53d9cac5c swift_errorInMain + 619 in libswiftCore.so
2 0x00005611330b8177 main + 54 in build

if let localTime {
    strftime(&buffer, buffer.count, "%Y-%m-%dT%H:%M:%S%z", localTime)
}