Cannot use ldflags to set build-time go variables

[andytynan]

Desired behaviour

When building a go module, it is useful to have a version string "burned" into the binary.
In go, this is accomplished by using the go tool link option -X, via the go build option -ldflags.
E.g.: go build -ldflags="-X BUILD_VERSION=${VERSION}"
That command tells the linker to use the value in the bash variable VERSION as the initial value for the go variable BUILD_VERSION.

Current behaviour

Although the -ldflags line is used internally in the gopy code, and passed to the go build command, it is hard-coded to set just the -s and -w options, based on the gopy option --symbols.

gopy/cmd_build.go

Line 193 in 1d7f3a2

args = append(args, "-ldflags=-s -w")

Possible solution

Add a new gopy build option --ldflags that would pass its value on to go build.
The -w and -s flags could be de-duplicated if the gopy --symbols is set, and those flags were also included in the --ldflags value.

Development

I plan to fork the project and fix this for my own requirements shortly, and would be grateful if a contributor could revierw the change once tested, and see whether they consider it a useful enhancement, to be merged into the main project.