Build with '-{gc,asm}flags all=-trimpath=' for reproducibility
Borrowed from Debian dh-golang (1.38) for reproducible build. See also https://github.com/restic/restic/issues/2061
Hi Eric, please feel free to massage this patch as you see fit. In particular, the addition of "all=" make it works for Go (>= 1.10) only, for better or for worse.
Cheers, Anthony