Backport from xs.

xs.h

@@ -64,6 +64,7 @@ d_char *xs_crop(d_char *str, int start, int end);
 d_char *xs_strip_chars(d_char *str, const char *chars);
 #define xs_strip(str) xs_strip_chars(str, " \r\n\t\v\f")
 d_char *xs_tolower(d_char *str);
+d_char *xs_str_prepend(d_char *str, const char *prefix);
 d_char *xs_list_new(void);
 d_char *xs_list_append_m(d_char *list, const char *mem, int dsz);
 #define xs_list_append(list, data) xs_list_append_m(list, data, xs_size(data))
@@ -489,6 +490,18 @@ d_char *xs_tolower(d_char *str)
 }
 
 
+d_char *xs_str_prepend(d_char *str, const char *prefix)
+/* prepends prefix into string */
+{
+    int sz = strlen(prefix);
+
+    str = xs_expand(str, 0, sz);
+    memcpy(str, prefix, sz);
+
+    return str;
+}
+
+
 /** lists **/
 
 d_char *xs_list_new(void)

xs_version.h

@@ -1 +1 @@
-/* e8f087f6b185939256227ea21b69f5f16f25a2dd */
+/* 38b055a19829fb788f1bb6917f76cc4830388e35 */