Fix Lintian warnings about wrong interpreter path

The command used for this change is as follows:

grep -rH "/usr/bin/env perl" * | cut -d: -f1 | xargs -n1 sed -i -e "s,/usr/bin/env perl,/usr/bin/perl,"

Gbp-Pq: Name 0002-Fix-Lintian-warnings-about-wrong-interpreter-path.patch

Reproducible BUILD_PATH_PREFIX_MAP

Make builds reproducible by honoring BUILD_PATH_PREFIX_MAP
Upstream has rejected the patch in this form and promised to implement an
alternative they are happy with instead. That hasn't happened yet though.

Bug: https://github.com/golang/go/issues/22491, https://github.com/golang/go/issues/16860
Forwarded: https://golang.org/cl/73291 (rejected upstream though)

Gbp-Pq: Name 0001-Reproducible-BUILD_PATH_PREFIX_MAP.patch

golang-1.12 (1.12.7-3) unstable; urgency=medium

  * Set GOCACHE to fix a FTBFS. (Closes: #933958)

[dgit import unpatched golang-1.12 1.12.7-3]

Import golang-1.12_1.12.7-3.debian.tar.xz

[dgit import tarball golang-1.12 1.12.7-3 golang-1.12_1.12.7-3.debian.tar.xz]

Import golang-1.12_1.12.7.orig.tar.gz

[dgit import orig golang-1.12_1.12.7.orig.tar.gz]