i'm trying to set up a derivation for
https://github.com/Xaymar/obs-StreamFX/tree/0.12.0b164

in a package array (obs plugins in home manager, this is inside my larger system nix config, shouldn't matter between this and systemPackages), i have:

(pkgs.callPackage ./internal-stuff/obs/streamfx.nix {})

the contents of streamfx.nix is

{
    fetchFromGitHub, stdenv, obs-studio, cmake, lib, qtbase ? qt6.qtbase, qt6, ffmpeg }: stdenv.mkDerivation rec {
    pname = "obs-streamfx";
    version = "0.12.0b164";

    src = fetchFromGitHub {
        owner = "Xaymar";
        repo = "obs-StreamFX";
        rev = version;
        sha256 = "0lf99y636pp0w0swwrg960z1gpl7v9r8vfyinbajnwrcaawcfnsj";
        fetchSubmodules = true;
    };

    #patches = [
    #   ./streamfx-cmake.patch
    #];

    cmakeFlags = [
        "-DSTRUCTURE_PACKAGEMANAGER=ON"
        "-DDOWNLOAD_QT=OFF"
        "-DVERSION=${version}"
        "-DENABLE_UPDATER=OFF"
    ];

    nativeBuildInputs = [ cmake ];
    buildInputs = [ obs-studio qtbase ffmpeg ];
    dontWrapQtApps = true;

    meta.broken = lib.versionOlder obs-studio.version "28";
}

the error i'm getting out of this, per nix log:

@nix { "action": "setPhase", "phase": "qtPreHook" }
qtPreHook
@nix { "action": "setPhase", "phase": "unpackPhase" }
unpacking sources
unpacking source archive /nix/store/71g0iqn2nvz2rbkr0sdp1hvgdd0lmvhq-source
source root is source
@nix { "action": "setPhase", "phase": "patchPhase" }
patching sources
@nix { "action": "setPhase", "phase": "configurePhase" }
configuring
fixing cmake files...
cmake flags: -DCMAKE_FIND_USE_SYSTEM_PACKAGE_REGISTRY=OFF -DCMAKE_FIND_USE_PACKAGE_REGISTRY=OFF -DCMAKE_EXPORT_NO_PACKAGE_REGISTRY=ON -DCMAKE_BUILD_TYPE=Release -DBUILD_TESTING=OFF -DCMAKE_INSTALL_LOCALEDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/share/locale -DCMAKE_INSTALL_LIBEXECDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/libexec -DCMAKE_INSTALL_LIBDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/lib -DCMAKE_INSTALL_DOCDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/share/doc/obs-streamfx -DCMAKE_INSTALL_INFODIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/share/info -DCMAKE_INSTALL_MANDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/share/man -DCMAKE_INSTALL_OLDINCLUDEDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/include -DCMAKE_INSTALL_INCLUDEDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/include -DCMAKE_INSTALL_SBINDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/sbin -DCMAKE_INSTALL_BINDIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/bin -DCMAKE_INSTALL_NAME_DIR=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164/lib -DCMAKE_POLICY_DEFAULT_CMP0025=NEW -DCMAKE_OSX_SYSROOT= -DCMAKE_FIND_FRAMEWORK=LAST -DCMAKE_STRIP=/nix/store/dq0xwmsk1g0i2ayg6pb7y87na2knzylh-gcc-wrapper-11.3.0/bin/strip -DCMAKE_RANLIB=/nix/store/dq0xwmsk1g0i2ayg6pb7y87na2knzylh-gcc-wrapper-11.3.0/bin/ranlib -DCMAKE_AR=/nix/store/dq0xwmsk1g0i2ayg6pb7y87na2knzylh-gcc-wrapper-11.3.0/bin/ar -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++ -DCMAKE_INSTALL_PREFIX=/nix/store/sgdiwz4w55bnccxpywn71nmlah55zshv-obs-streamfx-0.12.0b164 -DSTRUCTURE_PACKAGEMANAGER=ON -DDOWNLOAD_QT=OFF -DVERSION=0.12.0b164 -DENABLE_UPDATER=OFF 
CMake Error at CMakeLists.txt:49 (include):
  include could not find requested file:

    version


-- [StreamFX] This is a standalone build, please make sure you've followed the instructions.
CMake Error at CMakeLists.txt:83 (version):
  Unknown CMake command "version".


-- Configuring incomplete, errors occurred!

#nixOS

edit to note:

the relevant section of cmakelists.txt is:

# Search Paths
set(CMAKE_MODULE_PATH
    "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"
    "${CMAKE_CURRENT_SOURCE_DIR}/cmake/clang"
    "${CMAKE_CURRENT_SOURCE_DIR}/cmake/version"
    "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
)

# Include
include("util")                         # CacheClear, CacheSet
include("version")                      # version()
include("CheckIPOSupported")            # check_ipo_supported

the cmake/version directory of the git repo exists in a submodule, but fetchSubmodules is true (it was false for a bit but i've tried it both ways to the same result, so i think i'm just still not getting the submodules??)