AddBuildFlags adds the flags common to the build, clean, get, install, list, run, and test commands.

AddCoverFlags adds coverage-related flags to "cmd".

BuildInstallFunc is the action for installing a single package or executable.

FindExecCmd derives the value of ExecCmd to use.

NewBuilder returns a new Builder ready for use.

NewShell returns a new Shell.

AllowInstall returns a non-nil error if this invocation of the go command is allowed to install a.Target.

ExecCmd is the command to use to run user binaries.

Tests can override this by setting $TESTGO_TOOLCHAIN_VERSION.

VetExplicit records whether the vet flags were set explicitly on the command line.

VetFlags are the default flags to pass to vet.

VetTool is the path to an alternate vet tool binary.

An Action represents a single action in the action graph.

A Builder holds global state about a build.

A Shell runs shell commands and performs shell-like file system operations.

An Actor runs an action.

An ActorFunc is an Actor that calls the function.

BuildMode specifies the build mode: are we just building things or also installing the results?.