Gopherjs: Go 1.7 support

[benechols-wf]

Go1.7 beta is out now and would be awesome to support it (I think a lot of people will be upgrading quickly due to the performance and compiling improvements)

Not a huge hurry yet, just thought I would put in the ticket early :)

I started poking around and I think that changing runtime.go will fix half the issues

-const GOOS = sys.TheGoos
+const GOOS = sys.GOOS

And the other issue I don't fully understand (when trying to do a gopherjs build):

$GOROOT/src/runtime/error.go:70:9: invalid operation: e._type (variable of type *struct{_string *string}) has no field or method string

[dmitshur]

Great! Let's use this issue to track the development status of support for Go 1.7.

It's great that you already gave it a shot and shared some immediately visible issues to be resolved.

I'll likely start looking at this in the next few weeks, after I get some other tasks out of my pipeline.

[benechols-wf]

@shurcooL just a ping as 1.7 RC1 just came out and is slated for release end of the month :)

[dmitshur]

Roger that. I will try to look this weekend. :)

[neelance]

Some good progress for 1.7 can be found on the https://github.com/gopherjs/gopherjs/tree/go1.7 branch.

[dmitshur]

Go 1.7 has been released today.

https://blog.golang.org/go1.7

[dmitshur]

I downloaded 1.7 (go version go1.7 darwin/amd64), installed GopherJS on go1.7 branch and gave it a try on some of my largest GopherJS projects. They all seemingly worked without issues.

Looking at the CI output for that branch, it's not too surprising because most tests are passing, except for a handful. So we're quite close.

I'll make a PR off that branch.