guix build: Allow directories to be passed to --with-source.

* guix/scripts/build.scm (package-with-source)[tarball-base-name]: Gracefully
  handle file names that lack an extension.
  Pass #:recursive? #t to 'download-to-store'.
* guix/download.scm (download-to-store): Add #:recursive? parameter and pass
  it to 'add-to-store'.
* doc/guix.texi (Invoking guix build): Add an example of --with-source with a
  directory.

1 files changed, 7 insertions, 0 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index be7a292f084..c70d1000aed 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -3438,6 +3438,13 @@ candidates:
 guix build guile --with-source=../guile-2.0.9.219-e1bb7.tar.xz
 @end example
 
+@dots{} or to build from a checkout in a pristine environment:
+
+@example
+$ git clone git://git.sv.gnu.org/guix.git
+$ guix build guix --with-source=./guix
+@end example
+
 @item --no-grafts
 Do not ``graft'' packages.  In practice, this means that package updates
 available as grafts are not applied.  @xref{Security Updates}, for more