git: Add metadata to the result of `git archive`

When building Xen from a source tarball, commit information is usually lost,
especially if the tarball was generated from a tag.

Have `git archive` automatically fill in metadata at the point of creating the
archive, which is especially useful when using web snapshot links such as:

  http://xenbits.xen.org/gitweb/?p=xen.git;a=snapshot;h=HEAD;sf=tgz

to obtain the tarball.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>

diff --git a/.gitarchive-info b/.gitarchive-info
new file mode 100644 (file)
index 0000000..83e5b86
--- /dev/null
+++ b/.gitarchive-info
@@ -0,0 +1,2 @@
+Changeset: $Format:%H$
+Commit date: $Format:%cD$

diff --git a/.gitattributes b/.gitattributes
new file mode 100644 (file)
index 0000000..f7bf506
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1 @@
+.gitarchive-info export-subst