$NetBSD$

Stop checking every environment variable.

--- src/github.com/cockroachdb/cockroach/Makefile.orig	2020-11-25 14:36:31.000000000 +0000
+++ src/github.com/cockroachdb/cockroach/Makefile
@@ -1834,5 +1834,5 @@ build/variables.mk: Makefile build/archi
 # any environment variable becomes a make variable and environments
 # are dirty. For instance, my includes GREP_COLOR.
 include build/variables.mk
-$(foreach v,$(filter-out $(strip $(VALID_VARS)),$(.VARIABLES)),\
-	$(if $(findstring command line,$(origin $v)),$(error Variable '$v' is not recognized by this Makefile)))
+#$(foreach v,$(filter-out $(strip $(VALID_VARS)),$(.VARIABLES)),\
+#	$(if $(findstring command line,$(origin $v)),$(error Variable '$v' is not recognized by this Makefile)))