From 5c380416a80cc32ad81c7b567101fea1a487af2f Mon Sep 17 00:00:00 2001
From: Jack Moffitt <jack@metajack.im>
Date: Thu, 22 Aug 2013 20:32:52 -0600
Subject: [PATCH] Fix backup-rust target to ignore failures.

---
 Makefile.in | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/Makefile.in b/Makefile.in
index bb7a5d4e0a1..d5a6716c6e5 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -318,10 +318,14 @@ endif
 # Because Rust takes a very long time to build and changes infrequently,
 # the bots want to reuse it between builds. They can do so by running
 # `make backup-rust` and `make restore-rust`.
+#
+# backup-rust is run before the build directory is cleaned. if it fails, that's ok.
+#
+# restore-rust is run after configure and before invoking make. if it fails, we must abort.
 
 .PHONY: backup-rust restore-rust
 backup-rust:
-	mv src/compiler/rust ..
+	-mv src/compiler/rust ..
 
 restore-rust:
 	if [ -d ../rust ]; then rm -rf src/compiler/rust; mv ../rust src/compiler/; fi