Update cl.xml for PoCL vendor ID in vk.xml (#506)

Author: franz

xml/cl.xml

@@ -1093,7 +1093,9 @@ server's OpenCL/api-docs repository.
         </comment>
         <unused start="0x10000" end="0x10003" comment="These Khronos vendor IDs are already assigned in vk.xml"/>
         <enum value="0x10004" name="CL_KHRONOS_VENDOR_ID_CODEPLAY" comment="Codeplay Software Ltd."/>
-        <unused start="0x10005" end="0x1FFFF" comment="See vk.xml for the next available Khronos vendor ID"/>
+        <unused start="0x10005" end="0x10005" comment="These Khronos vendor IDs are already assigned in vk.xml"/>
+        <enum value="0x10006" name="CL_KHRONOS_VENDOR_ID_POCL" comment="PoCL (http://portablecl.org/)"/>
+        <unused start="0x10007" end="0x1FFFF" comment="See vk.xml for the next available Khronos vendor ID"/>
     </enums>
 
     <enums start="0x0900" end="0x09FF" name="cl_platform_info" vendor="Khronos">