pkg attempts to build unnecessary and illogical targets

[phoikoi]

Upon specifying -t node7-linux-armv7 as the only target on a MacOS host, pkg downloads the armv7 base binary, but then starts to (attempt to) build a macos-armv7 base binary from source. This is illogical and unnecessary. I stopped it after noticing what it was doing, so I don't know if it would subsequently attempt to make a win-armv7 binary as well.
Transcript of attempted build:

$ pkg . --targets node7-linux-armv7
> Fetching base Node.js binaries to: ~/.pkg-cache
  fetched-v7.6.0-linux-armv7   [====================] 100%
  fetched-v7.6.0-macos-armv7   [====================] 100%
> Error! 404 Not Found
  https://github.com/zeit/pkg-fetch/releases/download/v1.9/uploaded-v1.9-node-v7.6.0-macos-armv7
> Asset 'v1.9/uploaded-v1.9-node-v7.6.0-macos-armv7' not found by direct link
> Not found in GitHub releases:
  {"tag":"v1.9","name":"uploaded-v1.9-node-v7.6.0-macos-armv7"}
> Building base binary from source:
  built-v7.6.0-macos-armv7
> Cloning Node.js repository from GitHub...
  git                          [========            ] 40%^C

Update: it does not attempt to make a macos-armv7 target when running on an actual linux-armv7 host (i.e., a Raspberry Pi 3). So it's not using the default linux,macos,win targets, but apparently trying to build a host-native version as well as the specified target.
Update 2: Upon attempting a node6-macos-x64 build on the armv7 host, the same pattern followed where pkg attempted to build a host-native version of the target arch (in this case, node6-linux-x64) but crashed in the attempt:

$ pkg . -t node6-macos-x64
> Fetching base Node.js binaries to: ~/.pkg-cache
  fetched-v6.10.0-macos-x64    [====================] 100%
  fetched-v6.10.0-linux-x64    [====================] 100%
/home/pi/.pkg-cache/v1.9/fetched-v6.10.0-linux-x64: 1: /home/pi/.pkg-cache/v1.9/fetched-v6.10.0-linux-x64: cannot create $�x@��x@@%@@@@@�@@@@L�kL�k �k����(s� 0�k0��0��0@@DDP�td�O住住����Q�td/lib64/ld-linux-x86-64.so.2GNUGNU�N�ޞ:^�m�zw���3�m���A�3G
       : Directory nonexistent
/home/pi/.pkg-cache/v1.9/fetched-v6.10.0-linux-x64: 1: /home/pi/.pkg-cache/v1.9/fetched-v6.10.0-linux-x64: ELF: not found
/home/pi/.pkg-cache/v1.9/fetched-v6.10.0-linux-x64: 4: /home/pi/.pkg-cache/v1.9/fetched-v6.10.0-linux-x64: Syntax error: ")" unexpected
> Error! Error: Not able to compile for 'x64' here
    at Socket.<anonymous> (/home/pi/.npm/lib/node_modules/pkg/lib-es5/producer.js:43:25)
    at emitOne (events.js:90:13)
    at Socket.emit (events.js:182:7)
    at onwriteError (_stream_writable.js:313:10)
    at onwrite (_stream_writable.js:331:5)
    at WritableState.onwrite (_stream_writable.js:89:5)
    at fireErrorCallbacks (net.js:448:13)
    at Socket._destroy (net.js:486:3)
    at WriteWrap.afterWrite (net.js:769:10)

[grempe]

Same issue. Build host is Mac OS.

$ pkg --target node7-linux-armv7 --out-dir dist .
> Fetching base Node.js binaries to: ~/.pkg-cache
  fetched-v7.6.0-macos-armv7   [====================] 100%
> Error! 404 Not Found
  https://github.com/zeit/pkg-fetch/releases/download/v1.9/uploaded-v1.9-node-v7.6.0-macos-armv7
> Asset 'v1.9/uploaded-v1.9-node-v7.6.0-macos-armv7' not found by direct link
> Not found in GitHub releases:
  {"tag":"v1.9","name":"uploaded-v1.9-node-v7.6.0-macos-armv7"}
> Building base binary from source:
  built-v7.6.0-macos-armv7
> Cloning Node.js repository from GitHub...
  git                          [====================] 100%
> Checking out v7.6.0
> Applying patches
> Compiling Node.js from sources...
  make                         [                    ] 0%

[TooTallNate]

To explain a bit: at this time pkg can do cross-platform-compilation (build for Windows on Linux), but not cross-CPU-compilation (build for ARM on x64). pkg _does_ work for ARM, but needs to be run on ARM hardware (Raspberry Pi, etc.).

As of https://github.com/zeit/pkg-fetch/commit/67c4a7b0823497704351638eb4216fb553006757 pkg will now throw an error when attempting to do this.