auto populate LDFLAGS

[sozercan]

seems like we might need to define LDFLAGS for each build (since we may not rely on existing make targets because of vendoring), can we do this in a centralized way

relevant to #7

[cpuguy83]

For go I think we can copy modules and not have to deal with vendoring. Example: https://gist.github.com/cpuguy83/1b75a3a88e5fa9fdf5caddcaa91e90f4

You can also use the GOFLAGS env var to set, e.g. GOFLAGS="-ldflags='<flags>'"

[cpuguy83]

This should be handled because you can either set it with GOFLAGS or pre-fetch go modules.