Embarassingly, using this option caused configuration parsing errors
because it was not added to the grammar.  ok?

diff /home/jrick/src/got
commit - b9a36ae5ebce5fb8ce9d944a31210917b32c71d8
path + /home/jrick/src/got
blob - 75ffe68ef694e38f5138920800c795cdc7b10080
file + libexec/got-read-gotconfig/parse.y
--- libexec/got-read-gotconfig/parse.y
+++ libexec/got-read-gotconfig/parse.y
@@ -115,6 +115,7 @@ grammar		: /* empty */
 		| grammar author '\n'
 		| grammar remote '\n'
 		| grammar allowed_signers '\n'
+		| grammar revoked_signers '\n'
 		;
 boolean		: STRING {
 			if (strcasecmp($1, "true") == 0 ||