No sccache (#26059)
Summary:
Proposed change:
Check whether sccache is available before running it to show statistics.
(If not available, simply skip it. Showing these stats isn't mandatory to build.)
https://github.com/pytorch/pytorch/issues/26058
Pull Request resolved: https://github.com/pytorch/pytorch/pull/26059
Differential Revision: D17364967
Pulled By: vincentqb
fbshipit-source-id: 0250c6ba5573bc0b292ae8e2188b3e1fa700409e
