diff --git a/src/option.c b/src/option.c
index 98bac5a..df81cf3 100644
--- a/src/option.c
+++ b/src/option.c
@@ -1932,7 +1932,7 @@
 	int	    cp_val,
 	char_u	    *varp_arg,
 	char	    *errbuf,
-	int	    errbuflen,
+	size_t	    errbuflen,
 	int	    *value_checked,
 	char	    **errmsg)
 {
diff --git a/src/optionstr.c b/src/optionstr.c
index 84c77cb..d8e22c0 100644
--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -229,7 +229,7 @@
 #endif
 
     static char *
-illegal_char(char *errbuf, int errbuflen, int c)
+illegal_char(char *errbuf, size_t errbuflen, int c)
 {
     if (errbuf == NULL)
 	return "";
@@ -527,7 +527,7 @@
     char_u	*value,
     int		opt_flags,	// OPT_LOCAL and/or OPT_GLOBAL
     char	*errbuf,
-    int		errbuflen)
+    size_t	errbuflen)
 {
     char_u	*s;
     char_u	**varp;
@@ -726,7 +726,7 @@
 	char_u *val,
 	char_u *flags,
 	char *errbuf,
-	int errbuflen)
+	size_t errbuflen)
 {
     char_u	*s;
 
@@ -4354,7 +4354,7 @@
     char_u	*oldval,		// previous value of the option
     char_u	*value,			// new value of the option
     char	*errbuf,		// buffer for errors, or NULL
-    int		errbuflen,		// length of error buffer
+    size_t	errbuflen,		// length of error buffer
     int		opt_flags,		// OPT_LOCAL and/or OPT_GLOBAL
     set_op_T    op,			// OP_ADDING/OP_PREPENDING/OP_REMOVING
     int		*value_checked)		// value was checked to be safe, no
diff --git a/src/proto/optionstr.pro b/src/proto/optionstr.pro
index 4ce9321..fecfcb1 100644
--- a/src/proto/optionstr.pro
+++ b/src/proto/optionstr.pro
@@ -8,7 +8,7 @@
 void set_string_option_direct(char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
 void set_string_option_direct_in_win(win_T *wp, char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
 void set_string_option_direct_in_buf(buf_T *buf, char_u *name, int opt_idx, char_u *val, int opt_flags, int set_sid);
-char *set_string_option(int opt_idx, char_u *value, int opt_flags, char *errbuf, int errbuflen);
+char *set_string_option(int opt_idx, char_u *value, int opt_flags, char *errbuf, size_t errbuflen);
 char *did_set_ambiwidth(optset_T *args);
 char *did_set_background(optset_T *args);
 char *did_set_backspace(optset_T *args);
@@ -121,7 +121,7 @@
 char *did_set_wildoptions(optset_T *args);
 char *did_set_winaltkeys(optset_T *args);
 char *did_set_wincolor(optset_T *args);
-char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char_u *value, char *errbuf, int errbuflen, int opt_flags, set_op_T op, int *value_checked);
+char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char_u *value, char *errbuf, size_t errbuflen, int opt_flags, set_op_T op, int *value_checked);
 int expand_set_ambiwidth(optexpand_T *args, int *numMatches, char_u ***matches);
 int expand_set_background(optexpand_T *args, int *numMatches, char_u ***matches);
 int expand_set_backspace(optexpand_T *args, int *numMatches, char_u ***matches);
diff --git a/src/structs.h b/src/structs.h
index 6d9dcbb..de02bc6 100644
--- a/src/structs.h
+++ b/src/structs.h
@@ -4969,7 +4969,7 @@
     // message (when it is not NULL).
     char	*os_errbuf;
     // length of the error buffer
-    int		os_errbuflen;
+    size_t	os_errbuflen;
 } optset_T;
 
 /*
diff --git a/src/version.c b/src/version.c
index 064b813..16d13b9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -705,6 +705,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2150,
+/**/
     2149,
 /**/
     2148,