The QEMU tree often has dirty submodules in it but this will confuse
things as git stash is not going to save their state directly. They
are likely just dirty from build files anyway. Ignore them in the
diff-index command.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
---
 tests/docker/Makefile.include | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/docker/Makefile.include b/tests/docker/Makefile.include
index ff580edfad..2a560a5327 100644
--- a/tests/docker/Makefile.include
+++ b/tests/docker/Makefile.include
@@ -20,7 +20,7 @@ IMAGES ?= %
 # Make archive from git repo $1 to tar.gz $2
 make-archive-maybe = $(if $(wildcard $1/*), \
 	$(call quiet-command, \
-		(cd $1; if git diff-index --quiet HEAD -- 2>/dev/null; then \
+		(cd $1; if git diff-index --quiet --ignore-submodules HEAD -- 2>/dev/null; then \
 			git archive -1 HEAD --format=tar.gz; \
 		else \
 			git archive -1 $$(git stash create) --format=tar.gz; \
-- 
2.13.0