Merge pull request #4048 from kou/export-mrb-utf8-locale

Export mrb_utf8_from_locale() and mrb_locale_from_utf8()

include/mruby.h

@@ -994,8 +994,8 @@ MRB_API mrb_value mrb_str_new_static(mrb_state *mrb, const char *p, size_t len);
 #define mrb_str_new_lit(mrb, lit) mrb_str_new_static(mrb, (lit), mrb_strlen_lit(lit))
 
 #ifdef _WIN32
-char* mrb_utf8_from_locale(const char *p, int len);
-char* mrb_locale_from_utf8(const char *p, int len);
+MRB_API char* mrb_utf8_from_locale(const char *p, int len);
+MRB_API char* mrb_locale_from_utf8(const char *p, int len);
 #define mrb_locale_free(p) free(p)
 #define mrb_utf8_free(p) free(p)
 #else