This makes it easier to run the uninstalled daemon.
* nix/local.mk (libstore_a_CPPFLAGS): Append "/guix" to
NIX_LIBEXEC_DIR.
* build-aux/pre-inst-env.in (NIX_LIBEXEC_DIR): Adjust comment.
* nix/libstore/builtins.cc (builtinDownload): Remove SUBDIR and its
use.
* nix/libstore/local-store.cc (runAuthenticationProgram): Ditto.
* nix/libstore/gc.cc (addAdditionalRoots): Remove "/guix" prefix.
* nix/nix-daemon/guix-daemon.cc (main): Ditto.
* guix/scripts/perform-download.scm (perform-download): Add
#:print-build-trace? and pass it to 'url-fetch'.
(guix-perform-download): Define 'print-build-trace?' and pass it to
'perform-download'.
* guix/build/download.scm (ftp-fetch): Add #:print-build-trace? and
honor it.
(url-fetch): Likewise.
* nix/libstore/builtins.cc (builtinDownload): Set _NIX_OPTIONS
environment variable.
Reported by rohit yadav <rohityadav@utexas.edu>
at <https://lists.gnu.org/archive/html/guix-devel/2017-02/msg00191.html>.
This fixes a regression whereby 'guix perform-download' would always see
NIX_STORE as unset and thus use "/gnu/store", leading it to miscompute
the hydra.gnu.org content-addressed URLs when the store file name is not
"/gnu/store".
* nix/libstore/builtins.cc (builtinDownload): Add 'setenv' call for
'NIX_STORE'.
