utils: Add a #:follow-symlinks? parameter to `copy-recursively'.

* guix/build/utils.scm (copy-recursively): Turn `log' into a keyword
  parameter.  Add the `follow-symlinks?' parameter and honor it.

utils: Add `delete-file-recursively'.

* guix/build/utils.scm (delete-file-recursively): New procedure.

Merge branch 'master' into core-updates

Conflicts:
	Makefile.am
	guix/scripts/gc.scm
	guix/scripts/package.scm
	guix/ui.scm
	tests/guix-package.sh

guix: build: Add "share/pkgconfig" to PKG_CONFIG_PATH, as used by xorg.

* guix/build/gnu-build-system.scm (set-paths): Add "share/pkgconfig"
     to PKG_CONFIG_PATH.

Add (guix build-system perl).

* guix/build-system/perl.scm, guix/build/perl-build-system.scm: New files.
* Makefile.am (MODULES): Add them.
* guix/build-system/gnu.scm (standard-inputs): Make public.

download: Adjust to `http-get*' deprecation.

* guix/build/download.scm (http-fetch): Adjust to use #:streaming? when
  using Guile 2.0.8+.

Patch-shebang: Do not add space after interpreter without argument.

* guix/build/utils.scm (patch-shebang): Do not add a space after a command
  interpreter not followed by an argument; this made two tests of
  coreutils fail.

Patch-shebang: Handle "#!/usr/bin/env command"

* guix/build/utils.scm (patch-shebang): Handle replacement of
   "#!.*/env CMD ARGS" by "#!/nix/store/path/.../to/CMD ARGS".

download: Adjust to `http-get*' deprecation.

* guix/build/download.scm (http-fetch): Adjust to use #:streaming? when
  using Guile 2.0.8+.

union: Don't warn when colliding leaves point to the same file.

* guix/build/union.scm (union-build)[resolve-collision]: Pass LEAVES
  through `delete-duplicates'; warn iff the result contains more than
  one item.

union: Delete duplicates when passed the same input several times.

* guix/build/union.scm (union-build): Prepend "." to the result of
  `union-tree', to match the expectations of `delete-duplicate-leaves'.
  Don't do mkdir when SUBDIR is ".".
* tests/union.scm ("union-build"): Keep duplicates in %BOOTSTRAP-INPUTS.

download: Follow HTTP redirection upon 301 "moved permanently".

* guix/build/download.scm (http-fetch): Follow redirections upon 301.
  This is what `downloads.sourceforge.net' returns, for instance.

download: Add HTTPS support.

* guix/build/download.scm: Autoload (gnutls).
  (tls-wrap): New procedure.
  (open-connection-for-uri): Add support for `https'.  Wrap the socket
  with `tls-wrap' in that case.
  (url-fetch): Add `https'.
* guix/download.scm (gnutls-derivation): New procedure.
  (url-fetch)[need-gnutls?]: New variable.
  Call `gnutls-derivation' when NEED-GNUTLS? is true, and add its output
  to the `GUILE_LOAD_PATH' env. var. in that case.

Merge branch 'core-updates'

Conflicts:
	guix/build/union.scm

download: Abbreviate URLs when displaying the progress report.

* guix/build/download.scm (uri-abbreviation): New procedure.
  (ftp-fetch, http-fetch): Use it instead of `uri->string' when calling
  `progress-proc'.  Reported by Andreas Enge.

build-system/gnu: Improve support for "lib" outputs; support "doc" outputs.

* guix/build/gnu-build-system.scm (configure)[package-name]: New
  procedure.
  When LIBDIR is true and INCLUDEDIR is false, add
  --includedir=LIBDIR/include.
  Add support for --docdir when a "doc" output exists.

union: Detect collisions, and delete duplicate leaves.

* guix/build/union.scm (delete-duplicate-leaves): New procedure.
  (union-build)[leaf=?, resolve-collision]: New procedures.
  Use `delete-duplicate-leaves' on the result of `tree-union'.
* tests/union.scm ("delete-duplicate-leaves, default",
  "delete-duplicate-leaves, file names"): New tests.

download: Report the progress of HTTP downloads.

* guix/build/download.scm (http-fetch): Rename `bv' to `bv-or-port'.
  Use `http-get*' followed by `dump-port' when the former is available,
  and pass a progress procedure to `dump-port'.

download: Report the progress of FTP downloads.

* guix/build/download.scm (progress-proc): New procedure.
  (ftp-fetch): Call `ftp-size' on URI.  Use `progress-proc', and pass
  the result to `dump-port', along with #:buffer-size.

Merge branch 'master' into core-updates

Conflicts:
	build-aux/download.scm
	distro/packages/autotools.scm
	distro/packages/base.scm
	distro/packages/bootstrap.scm
	distro/packages/lsh.scm
	distro/packages/make-bootstrap.scm
	distro/packages/ncurses.scm
	distro/packages/perl.scm
	tests/derivations.scm
	tests/union.scm