Makefile: workaround Eclipse Gitlab rate limiting

Got this while pulling in the entire set of deps:
"""
remote: You have reached the limit of requests you can make to Eclipse GitLab.
This could be caused by too many open tabs, which query the GitLab server in
the background. Please close unused tabs, or put them to sleep so they don't
issue requests needlessly.
"""

Change-Id: I5866154a6af88875a446e092f0926cdc4a1a9fc4
---
M Makefile
1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/Makefile b/Makefile
index 4b6a5e2..c399714 100644
--- a/Makefile
+++ b/Makefile
@@ -65,9 +65,11 @@
 
 default: deps all
 
+# Eclipse GitLab has rate limiting and sometimes to many concurrent conns fail.
+# If -jN fails, retry with -j1.
 .PHONY: deps
 deps:
-	$(MAKE) $(PARALLEL_MAKE) -C deps
+	($(MAKE) $(PARALLEL_MAKE) -C deps || $(MAKE) -j1 -C deps)
 
 # deps-update target for backwards compat; now does the same as 'make deps'
 .PHONY: deps-update

