[ostree] ostbuild: Take advantage of link cache

[Colin Walters <walters src gnome org>]

commit 863384b90d25abb1c0770db8156cb3cc99810a96
Author: Colin Walters <walters verbum org>
Date:   Fri Apr 13 16:10:40 2012 -0400

    ostbuild: Take advantage of link cache
    
    This greatly speeds up construction of buildroots.

 .../pyostbuild/builtin_chroot_compile_one.py       |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/ostbuild/pyostbuild/builtin_chroot_compile_one.py b/src/ostbuild/pyostbuild/builtin_chroot_compile_one.py
index fa29be9..0c6a96c 100755
--- a/src/ostbuild/pyostbuild/builtin_chroot_compile_one.py
+++ b/src/ostbuild/pyostbuild/builtin_chroot_compile_one.py
@@ -45,9 +45,12 @@ class OstbuildChrootCompileOne(builtins.Builtin):
             checkout_trees.append((buildname, '/runtime'))
             checkout_trees.append((buildname, '/devel'))
 
+        link_cache_dir = os.path.join(self.workdir, 'link-cache')
+        fileutil.ensure_dir(link_cache_dir)
+
         for (branch, rootpath) in checkout_trees:
             run_sync(['ostree', '--repo=' + self.repo,
-                      'checkout', '--user-mode',
+                      'checkout', '--user-mode', '--link-cache=' + link_cache_dir,
                       '--union', '--subpath=' + rootpath,
                       branch, dirpath])