diff --git a/src/chars.c b/src/chars.c
index 9ae88782..e6b5783d 100644
--- a/src/chars.c
+++ b/src/chars.c
@@ -545,7 +545,7 @@ char *mbrevstrcasestr(const char *haystack, const char *needle,
 
 #if !defined(NANO_TINY) || defined(ENABLE_JUSTIFY)
 /* This function is equivalent to strchr() for multibyte strings. */
-char *mbstrchr(const char *string, const char *chr)
+const char *mbstrchr(const char *string, const char *chr)
 {
 #ifdef ENABLE_UTF8
 	if (using_utf8) {
diff --git a/src/prototypes.h b/src/prototypes.h
index 1eda8be7..224492c6 100644
--- a/src/prototypes.h
+++ b/src/prototypes.h
@@ -233,7 +233,7 @@ char *mbstrcasestr(const char *haystack, const char *needle);
 char *revstrstr(const char *haystack, const char *needle, const char *pointer);
 char *mbrevstrcasestr(const char *haystack, const char *needle, const char *pointer);
 #if !defined(NANO_TINY) || defined(ENABLE_JUSTIFY)
-char *mbstrchr(const char *string, const char *chr);
+const char *mbstrchr(const char *string, const char *chr);
 #endif
 #ifndef NANO_TINY
 char *mbstrpbrk(const char *string, const char *accept);
diff --git a/src/winio.c b/src/winio.c
index 7865d425..92b12a71 100644
--- a/src/winio.c
+++ b/src/winio.c
@@ -349,7 +349,7 @@ void implant(const char *string)
 int get_code_from_plantation(void)
 {
 	if (*plants_pointer == '{') {
-		char *closing = strchr(plants_pointer + 1, '}');
+		const char *closing = strchr(plants_pointer + 1, '}');
 
 		if (!closing)
 			return MISSING_BRACE;
@@ -380,7 +380,7 @@ int get_code_from_plantation(void)
 
 		return PLANTED_A_COMMAND;
 	} else {
-		char *opening = strchr(plants_pointer, '{');
+		const char *opening = strchr(plants_pointer, '{');
 		unsigned char firstbyte = *plants_pointer;
 		int length;