patch 7.4.2044
Problem:    filter() and map() either require a string or defining a function.
Solution:   Support lambda, a short way to define a function that evaluates an
            expression. (Yasuhiro Matsumoto, Ken Takata)
diff --git a/src/Makefile b/src/Makefile
index 021cf21..f6d60c3 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2046,6 +2046,7 @@
 	test_join \
 	test_json \
 	test_jumps \
+	test_lambda \
 	test_langmap \
 	test_largefile \
 	test_lispwords \