wined3d: Add extension detection for ARB_depth_texture.

dlls/wined3d/directx.c

@@ -63,6 +63,7 @@ static const struct {
 
     /* ARB */
     {"GL_ARB_color_buffer_float",           ARB_COLOR_BUFFER_FLOAT,         0                           },
+    {"GL_ARB_depth_texture",                ARB_DEPTH_TEXTURE,              0                           },
     {"GL_ARB_draw_buffers",                 ARB_DRAW_BUFFERS,               0                           },
     {"GL_ARB_fragment_program",             ARB_FRAGMENT_PROGRAM,           0                           },
     {"GL_ARB_fragment_shader",              ARB_FRAGMENT_SHADER,            0                           },

dlls/wined3d/wined3d_gl.h

@@ -3384,6 +3384,7 @@ typedef enum _GL_SupportedExt {
   WINED3D_GL_EXT_NONE,
   /* ARB */
   ARB_COLOR_BUFFER_FLOAT,
+  ARB_DEPTH_TEXTURE,
   ARB_DRAW_BUFFERS,
   ARB_FRAGMENT_PROGRAM,
   ARB_FRAGMENT_SHADER,