Using additional .dll files

i had that issue with hitman contracts and found that using ThirteenAG's Ultimate ASI Loader and putting the widescreen fix stuff in the scripts folder with the dll renamed to an asi instead.
Though i'd advise that you have reshade as the d3d9.dll in the main folder and have the asi loader itself as one of the other dll's the game calls that it supports

PS: if you plan on introducing dgvoodoo2 into the pipeline, have reshade as dxgi.dll and have dgv2 do the translation from d3d9 to d3d11 before putting reshade into the pipeline

ReShade doesn't have proxy library functions, however .DLL injectors and the ASI loader as recommended by JJXB are good alternatives.

For .DLL injectors, such as something like ENBInjector, you just have to rename one of the .DLLs. For example, rename the ReShade dxgi.dll to something like rs.dll, then set up the injector's .ini file to point to your game .exe and the renamed .dll.