build: try creating the go bin directory

[robmonte]

Currently if the $GOPATH/bin directory does not exist, the binary will fail to be copied to the location.

I don't believe an if statement is needed to check for directory existence before the mkdir command, it simply does nothing when the directory already exists.

Closes #7170

[raymonstah]

Curious if this stemmed from an open issue.

[robmonte]

Curious if this stemmed from an open issue.

@raymonstah Not that I've seen, no. I encountered this myself when setting up a fresh EC2 instance to build and run Vault, and thought it'd be a good idea. However I came across this old issue: #7170

It kinda makes sense to me that some users with GOBIN set may want it in that location. Though I think this location is usually meant for Go packages when using go install and not technically for build artifacts? At least that's my understanding if someone can correct me.

 

Curious what others would think of something like this for line 53:
IFS=: FIRST=($GOPATH) BIN_PATH=${GOBIN:-${FIRST}/bin}

This sets BIN_PATH to the values in this order:

1. If GOBIN is set, always set BIN_PATH to GOBIN (ignore GOPATH)
2. If only GOPATH is set, set BIN_PATH to FIRST, which itself is set to the first element of GOPATH with /bin appended
3. If neither are set, BIN_PATH remains unset (uses Go's default of $HOME/go)

[ncabatoff]

This might warrant a changelog entry, not so much for vault users as for vault packagers; conceivably this might break someone's build script.