diff --git a/src/config/options.c b/src/config/options.c
index f152438d1..7c20e11fc 100644
--- a/src/config/options.c
+++ b/src/config/options.c
@@ -159,7 +159,7 @@ static int no_autocreate = 0;
 
 /* Get record of option of given name, or NULL if there's no such option. */
 struct option *
-get_opt_rec(struct option *tree, unsigned char *name_)
+get_opt_rec(struct option *tree, const unsigned char *name_)
 {
 	struct option *option;
 	unsigned char *aname = stracpy(name_);
@@ -231,7 +231,7 @@ get_opt_rec(struct option *tree, unsigned char *name_)
  * do not create the option if it doesn't exist and there's autocreation
  * enabled. */
 struct option *
-get_opt_rec_real(struct option *tree, unsigned char *name)
+get_opt_rec_real(struct option *tree, const unsigned char *name)
 {
 	struct option *opt;
 
diff --git a/src/config/options.h b/src/config/options.h
index 7ffb54247..77e2a1572 100644
--- a/src/config/options.h
+++ b/src/config/options.h
@@ -208,8 +208,8 @@ extern void checkout_option_values(struct option_resolver *resolvers,
  * use get_opt_type() and add_opt_type(). For command line options, you want to
  * use get_opt_type_tree(cmdline_options, "option"). */
 
-extern struct option *get_opt_rec(struct option *, unsigned char *);
-extern struct option *get_opt_rec_real(struct option *, unsigned char *);
+extern struct option *get_opt_rec(struct option *, const unsigned char *);
+extern struct option *get_opt_rec_real(struct option *, const unsigned char *);
 #ifdef CONFIG_DEBUG
 extern union option_value *get_opt_(unsigned char *, int, enum option_type, struct option *, unsigned char *);
 #define get_opt(tree, name, type) get_opt_(__FILE__, __LINE__, type, tree, name)