[WIP PATCH] test: make test-serially to run test serially

[Tomi Ollila]

This is easier and less error prone than mistyping NOTMUCH_TEST_SERIALIZE
manually from command line (mistype make test-serially and it just doesn't
work)
---

quick first version. this works, but someone(tm) w/ native english experience
could say how the naming sounds like...

 test/Makefile.local | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/test/Makefile.local b/test/Makefile.local
index 47244e8f0956..3c5e7e9cf33b 100644
--- a/test/Makefile.local
+++ b/test/Makefile.local
@@ -76,6 +76,9 @@ else
 endif
 endif
 
+test-serially: export NOTMUCH_TEST_SERIALIZE=t
+test-serially: test
+
 check: test
 
 SRCS := $(SRCS) $(test_srcs)
-- 
2.13.3