diff --git a/src/option.c b/src/option.c
index e6c05ec..f78d48d 100644
--- a/src/option.c
+++ b/src/option.c
@@ -4438,7 +4438,7 @@
 	    afterchar = arg[len];
 
 	    /* skip white space, allow ":set ai  ?" */
-	    while (vim_iswhite(arg[len]))
+	    while (VIM_ISWHITE(arg[len]))
 		++len;
 
 	    adding = FALSE;
@@ -4562,7 +4562,7 @@
 		    }
 		}
 		if (vim_strchr((char_u *)"?!&<", nextchar) != NULL
-			&& arg[1] != NUL && !vim_iswhite(arg[1]))
+			&& arg[1] != NUL && !VIM_ISWHITE(arg[1]))
 		{
 		    errmsg = e_trailing;
 		    goto skip;
@@ -4620,7 +4620,7 @@
 			(void)show_one_termcode(key_name, p, TRUE);
 		}
 		if (nextchar != '?'
-			&& nextchar != NUL && !vim_iswhite(afterchar))
+			&& nextchar != NUL && !VIM_ISWHITE(afterchar))
 		    errmsg = e_trailing;
 	    }
 	    else
@@ -4660,7 +4660,7 @@
 			 * ":set invopt": invert
 			 * ":set opt" or ":set noopt": set or reset
 			 */
-			if (nextchar != NUL && !vim_iswhite(afterchar))
+			if (nextchar != NUL && !VIM_ISWHITE(afterchar))
 			{
 			    errmsg = e_trailing;
 			    goto skip;
@@ -4714,7 +4714,8 @@
 				    || (long *)varp == &p_wcm)
 				&& (*arg == '<'
 				    || *arg == '^'
-				    || (*arg != NUL && (!arg[1] || vim_iswhite(arg[1]))
+				    || (*arg != NUL
+					&& (!arg[1] || VIM_ISWHITE(arg[1]))
 					&& !VIM_ISDIGIT(*arg))))
 			{
 			    value = string_to_key(arg);
@@ -4730,7 +4731,7 @@
 			     * hex numbers. */
 			    vim_str2nr(arg, NULL, &i, STR2NR_ALL,
 							     &value, NULL, 0);
-			    if (arg[i] != NUL && !vim_iswhite(arg[i]))
+			    if (arg[i] != NUL && !VIM_ISWHITE(arg[i]))
 			    {
 				errmsg = e_invarg;
 				goto skip;
@@ -4922,7 +4923,7 @@
 			     * do remove it for "\\\\machine\\path".
 			     * The reverse is found in ExpandOldSetting().
 			     */
-			    while (*arg && !vim_iswhite(*arg))
+			    while (*arg && !VIM_ISWHITE(*arg))
 			    {
 				if (*arg == '\\' && arg[1] != NUL
 #ifdef BACKSLASH_IN_FILENAME
@@ -5162,7 +5163,7 @@
 			else
 			{
 			    ++arg; /* jump to after the '=' or ':' */
-			    for (p = arg; *p && !vim_iswhite(*p); ++p)
+			    for (p = arg; *p && !VIM_ISWHITE(*p); ++p)
 				if (*p == '\\' && p[1] != NUL)
 				    ++p;
 			    nextchar = *p;
@@ -5190,7 +5191,7 @@
 	     */
 	    for (i = 0; i < 2 ; ++i)
 	    {
-		while (*arg != NUL && !vim_iswhite(*arg))
+		while (*arg != NUL && !VIM_ISWHITE(*arg))
 		    if (*arg++ == '\\' && *arg != NUL)
 			++arg;
 		arg = skipwhite(arg);