mesa: add support for glUnmapNamedBufferEXT()

Since the ARB DSA function glUnmapNamedBuffer() is only exposed
for 3.1 or above we make glUnmapNamedBuffer() an alias of
glUnmapNamedBufferEXT() rather than the other way around.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Signed-off-by: Marek Olšák <marek.olsak@amd.com>

src/mapi/glapi/gen/ARB_direct_state_access.xml

@@ -115,7 +115,7 @@
       <param name="access" type="GLbitfield" />
    </function>
 
-   <function name="UnmapNamedBuffer" no_error="true">
+   <function name="UnmapNamedBuffer" alias="UnmapNamedBufferEXT" no_error="true">
       <return type="GLboolean" />
       <param name="buffer" type="GLuint" />
    </function>

src/mapi/glapi/gen/EXT_direct_state_access.xml

@@ -174,6 +174,11 @@
       <param name="data" type="const GLvoid *" />
    </function>
 
+   <function name="UnmapNamedBufferEXT">
+      <return type="GLboolean" />
+      <param name="buffer" type="GLuint" />
+   </function>
+
    <!-- OpenGL 3.0 -->
 
    <function name="MapNamedBufferRangeEXT">

src/mapi/glapi/gen/static_data.py

@@ -1053,7 +1053,7 @@ offsets = {
     "TextureSubImage3D": 1017,
     "TransformFeedbackBufferBase": 1018,
     "TransformFeedbackBufferRange": 1019,
-    "UnmapNamedBuffer": 1020,
+    "UnmapNamedBufferEXT": 1020,
     "VertexArrayAttribBinding": 1021,
     "VertexArrayAttribFormat": 1022,
     "VertexArrayAttribIFormat": 1023,