diff --git a/Source/JavaScriptCore/API/JSStringRef.h b/Source/JavaScriptCore/API/JSStringRef.h
index aded736..30a6b73 100644
--- a/Source/JavaScriptCore/API/JSStringRef.h
+++ b/Source/JavaScriptCore/API/JSStringRef.h
@@ -32,6 +32,7 @@
 #include <stdbool.h>
 #endif
 #include <stddef.h> /* for size_t */
+#include <uchar.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -43,7 +44,7 @@ extern "C" {
 @typedef JSChar
 @abstract A Unicode character.
 */
-    typedef unsigned short JSChar;
+    typedef char16_t JSChar;
 #else
     typedef wchar_t JSChar;
 #endif
diff --git a/Source/WebKit2/Shared/API/c/WKString.h b/Source/WebKit2/Shared/API/c/WKString.h
index dd5b877..2df4a3b 100644
--- a/Source/WebKit2/Shared/API/c/WKString.h
+++ b/Source/WebKit2/Shared/API/c/WKString.h
@@ -28,6 +28,7 @@
 
 #include <WebKit2/WKBase.h>
 #include <stddef.h>
+#include <uchar.h>
 
 #ifndef __cplusplus
 #include <stdbool.h>
@@ -39,7 +40,7 @@ extern "C" {
 
 #if !defined(WIN32) && !defined(_WIN32) \
     && !((defined(__CC_ARM) || defined(__ARMCC__)) && !defined(__linux__)) /* RVCT */
-    typedef unsigned short WKChar;
+    typedef char16_t WKChar;
 #else
     typedef wchar_t WKChar;
 #endif