kaldi: Fix build

It looks like after a bump, CMake started passing `--git-dir=.git` as the first argument of `git rev-parse`.
But we do not really need to spoof `git` program now that Kaldi uses CMake’s `FetchContent` module.
We can just pass the path using configure flag directly:

https://cmake.org/cmake/help/latest/module/FetchContent.html#variable:FETCHCONTENT_SOURCE_DIR_%3CuppercaseName%3E

Git was also inadvertently used for generating `KALDI_PATCH_NUMBER`
in `VersionHelper`, to be potentially appended to `KALDI_VERSION`
but it was not actually being done by default.
We can set the variable directly to skip `VersionHelper`.

Also remove redundant `enableParallelBuild` since CMake enables it.

And drop separate `dev` output since Kaldi currently hardcodes
the `include/` directory so consumers would not be able to find them.
Splitting it out only removes 7 out of 303 MB.

pkgs/tools/audio/kaldi/default.nix

@@ -39,39 +39,9 @@ stdenv.mkDerivation {
     "-DBUILD_SHARED_LIBS=on"
     "-DBLAS_LIBRARIES=-lblas"
     "-DLAPACK_LIBRARIES=-llapack"
+    "-DFETCHCONTENT_SOURCE_DIR_OPENFST:PATH=${openfst}"
   ];
 
-  enableParallelBuilding = true;
-
-  preConfigure = ''
-    mkdir bin
-    cat > bin/git <<'EOF'
-    #!${stdenv.shell}
-    if [[ "$1" == "--version" ]]; then
-      # cmake checks this
-      ${git}/bin/git --version
-    elif [[ "$1" == "clone" ]]; then
-      # mock this call:
-
-      # https://github.com/kaldi-asr/kaldi/blob/c9d8b9ad3fef89237ba5517617d977b7d70a7ed5/cmake/third_party/openfst.cmake#L5
-      cp -r ${openfst} ''${@: -1}
-      chmod -R +w ''${@: -1}
-    elif [[ "$1" == "rev-list" ]]; then
-      # fix up this call:
-      # https://github.com/kaldi-asr/kaldi/blob/c9d8b9ad3fef89237ba5517617d977b7d70a7ed5/cmake/VersionHelper.cmake#L8
-      echo 0
-    elif [[ "$1" == "rev-parse" ]]; then
-      echo ${openfst.rev}
-      echo 0
-    fi
-    true
-    EOF
-    chmod +x bin/git
-    export PATH=$(pwd)/bin:$PATH
-  '';
-
-  outputs = [ "out" "dev" ];
-
   buildInputs = [
     openblas
     openfst
@@ -86,6 +56,16 @@ stdenv.mkDerivation {
     python3
   ];
 
+  preConfigure = ''
+    cmakeFlagsArray+=(
+      # Extract version without the need for git.
+      # https://github.com/kaldi-asr/kaldi/blob/71f38e62cad01c3078555bfe78d0f3a527422d75/cmake/VersionHelper.cmake
+      # Patch number is not actually used by default so we can just ignore it.
+      # https://github.com/kaldi-asr/kaldi/blob/71f38e62cad01c3078555bfe78d0f3a527422d75/CMakeLists.txt#L214
+      "-DKALDI_VERSION=$(cat src/.version)"
+    )
+  '';
+
   postInstall = ''
     mkdir -p $out/share/kaldi
     cp -r ../egs $out/share/kaldi