* guix/build-system/go.scm (go-build): Add install-source? key. * guix/build/go-build-system.scm (install-source): Check if install-source? is true.
* guix/build-system/go.scm, guix/build/go-build-system.scm: New files. * Makefile.am (MODULES): Add new files. * doc/guix.texi (Build Systems): Document the go-build-system.