doc: check-man: use COLUMNS env for width

That's the environment documented in ncurses(3) and man(1) from
the man-db.nongnu.org distribution of man.

diff --git a/Documentation/include.mk b/Documentation/include.mk
index 2878422c765c3baaccb2afb022b10bd2e15bd1d9..07b9f2a3f414734105906ad0c08856c9891dc55a 100644 (file)
--- a/Documentation/include.mk
+++ b/Documentation/include.mk
@@ -92,7 +92,7 @@ doc_install :: install-man
 # n.b. not sure if our usage of man(1) is portable or not, so not
 # enabled by default "check" target:
 # check :: check-man
-check_man = @echo CHECK80 $<;COLS=80 $(MAN) ./$^ | \
+check_man = @echo CHECK80 $<;COLUMNS=80 $(MAN) ./$^ | \
        $(AWK) '{gsub(/\b./,"")}length>80{print;err=1}END{exit(err)}' >&2
 
 %.1.cols : %.1; $(check_man)