(Could you also add GO386=387 to fix 32-bit builds?)
Do you have more details about the problem it should fix?
If I understand the documentation from https://golang.org/doc/install/source correctly, this option is either sse2 or 387 for non-sse2 support. However we don't support not SSE2 capable Windows machines anymore. Or do you want that for Linux builds?
For what it's worth, I do not support non-SSE2 obfs4proxy so if there are weird bugs, I will point and laugh at you.
It worked a year or so ago, thus if you added weird bugs after that, "I will point and laugh at you."