nvidia-x11: add GNU which to buildInputs (#156203)

This enables the runfile to successfully uncompress and extract without
having to fallback to "unpackManually" in "builder.sh"

pkgs/os-specific/linux/nvidia-x11/generic.nix

@@ -17,7 +17,7 @@
 }@args:
 
 { lib, stdenv, callPackage, pkgs, pkgsi686Linux, fetchurl
-, kernel ? null, perl, nukeReferences
+, kernel ? null, perl, nukeReferences, which
 , # Whether to build the libraries only (i.e. not the kernel module or
   # nvidia-settings).  Used to support 32-bit binaries on 64-bit
   # Linux.
@@ -93,6 +93,7 @@ let
     libPath = libPathFor pkgs;
     libPath32 = optionalString i686bundled (libPathFor pkgsi686Linux);
 
+    buildInputs = [ which ];
     nativeBuildInputs = [ perl nukeReferences ]
       ++ optionals (!libsOnly) kernel.moduleBuildDependencies;