time-travel-manifest: Use a separate cache per system.

* etc/time-travel-manifest.scm (<guix-instance-compiler>): Use a separate
cache per system so that parallel system evaluations do no step on each
other's toes.

diff --git a/etc/time-travel-manifest.scm b/etc/time-travel-manifest.scm
index f09659d..ab890dd 100644 (file)
--- a/etc/time-travel-manifest.scm
+++ b/etc/time-travel-manifest.scm
@@ -42,7 +42,7 @@
      ;; concurrent accesses are unsafe.
      (mparameterize %store-monad ((%repository-cache-directory
                                    (string-append (%repository-cache-directory)
-                                                  "/time-travel")))
+                                                  "/time-travel/" system)))
        (return (mkdir-p (%repository-cache-directory)))
        (latest-channel-derivation channels)))))