Slow to build

[anacrolix]

Builds are becoming relatively slow. Using go version go1.5.1 darwin/amd64, my build (presumably mostly link) time is:

real 0m2.879s
user 0m3.584s
sys 0m0.461s

For a very modest program. Building with -x shows that compile, and link are running only for the main package, which contains no fancy build directives.

I'm not sure how else to report this, but it is a concern that build times are inflating version over version.

[Thomasdezeeuw]

It's a know issue from converting the compiler from C to Go code. See #10765, #10571.

[rakyll]

Duplicate of #10571.