cmd/dist: make.bash -d failed with cmd/buildid not exist

[cherrymui]

What version of Go are you using (go version)?

tip (37b15ba)

make.bash -d failed with

$ ./make.bash -d
Building Go cmd/dist using /usr/local/google/home/cherryyz/src/go1.6.
Building Go toolchain1 using /usr/local/google/home/cherryyz/src/go1.6.
Building Go bootstrap cmd/go (go_bootstrap) using Go toolchain1.
compile version devel +37b15baa3b Mon Nov 6 16:36:34 2017 +0000 buildID=
Building Go toolchain2 using go_bootstrap and Go toolchain1.
compile version devel +37b15baa3b Mon Nov 6 16:36:34 2017 +0000 buildID=KI9kkrhYodePjDgqY485/T7nhZhGJyF5thLLiCbpW/VlTLnx_2M-iTehwqmBlF/4zrXY4jrpmB9m4HLcUbY
go tool dist: FAILED: /usr/local/google/home/cherryyz/src/go/pkg/tool/linux_amd64/buildid /usr/local/google/home/cherryyz/src/go/pkg/linux_amd64/runtime/internal/sys.a: fork/exec /usr/local/google/home/cherryyz/src/go/pkg/tool/linux_amd64/buildid: no such file or directory

I understand that this debug mode is not supposed for general use, but it would be good not to fail.
One option is to add cmd/buildid to "toolchain" in debug mode.

cc @rsc

[gopherbot]

Change https://golang.org/cl/76026 mentions this issue: cmd/dist: include "cmd/buildid" in toolchain in debug mode