Skip line-length warnings in man

Signed-off-by: Iustin Pop <iustin@google.com>
Reviewed-by: Michael Hanselmann <hansmi@google.com>

autotools/check-man

@@ -21,4 +21,6 @@
 set -e
 
 ! LC_ALL=C MANWIDTH=80 \
-man --warnings --encoding=utf8 --local-file "$1" 2>&1 >/dev/null | grep .
+  man --warnings --encoding=utf8 --local-file "$1" 2>&1 >/dev/null | \
+  grep -v -e "cannot adjust line" -e "can't break line" | \
+  grep .