cmd/link Command Line Interface

The go command and any other Go-aware build systems invoke cmd/link
to link a collection of packages into a single binary. By default, cmd/link will
present the same interface it does today:

	cmd/link main.a

produces a file named a.out, even if cmd/link does so by invoking the host
linker in external linking mode.

By default, cmd/link will decide the linking mode as follows: if the only

	"&\n", "& ",
	"|\n", "| ",
	"^\n", "^ ",
	"<\n", "< ",
	">\n", "> ",
	"=\n", "= ",
	"!\n", "! ", // not possible in gofmt today
	"(\n", "(",
	"[\n", "[", // not possible in gofmt today
	"{\n", "{",
	",\n", ",",
	".\n", ". ",
	":\n", ": ", // not possible in gofmt today

	"\n", ";",
)

// gofmtLine returns the gofmt-formatted string for an AST node,
// ensuring that it is on a single line.

			return false
		}
	}
	return true
}

// It would be nice if the error messages always began with
// the standard file:line: prefix,
// but that's not where we are today.
// It might be at the beginning but it might be in the middle of the printed instruction.
var fileLineRE = regexp.MustCompile(`(?:^|\()(testdata[/\\][\da-z]+\.s:\d+)(?:$|\)|:)`)

// Same as in test/run.go
var (