The logic to determine whether a filesystem root was in GOROOT or GOPATH
still relied on runtime.GOROOT(), whereas cmd/godoc was updated to copy
the goroot finding logic from standard library.
Hence, godoc is unable to determine if a filesystem is in GOROOT or not
when the binary is outside runtime.GOROOT(). So we expose a new variable
and set that from cmd/godoc to avoid copying the logic again for the 3rd time.
Fixesgolang/go#27162
Change-Id: I160dcdbdd262e671f09f7bf01c329be5eac280ad
Reviewed-on: https://go-review.googlesource.com/130796
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
ba93f9405e