d3dx9: D3DXCreateEffectxx

[Luis Busquets]

Please note that the current implementation of the functions

D3DXCreateEffectFromFileExW, D3DXCreateEffectFromFileExA, 
D3DXCreateEffectFromResourceExW, D3DXCreateEffectFromResourceExA

returns D3DERR_INVALIDCALL if defines are NULL. Actually, defines is an 
optional parameter and can indeed be NULL and return D3D_OK if 
everything else is correct.

I guess that that is the same for D3DXCreateEffectCompilerFromFileA, 
D3DXCreateEffectCompilerFromFileW