Add flatc

WORKSPACE

@@ -45,6 +45,12 @@ http_file(
     sha256 = "89a287444b5b3e98f88a945afa50ce937b8ffd1dcc59c555ad9b1baf855298c9",
 )
 
+http_file(
+    name = "flatbuffers_zip",
+    urls = ["https://github.com/google/flatbuffers/archive/refs/tags/v24.12.23.zip"],
+    sha256 = "c5cd6a605ff20350c7faa19d8eeb599df6117ea4aabd16ac58a7eb5ba82df4e7",
+)
+
 http_archive(
     name = "appcenter_sdk",
     urls = ["https://github.com/microsoft/appcenter-sdk-apple/releases/download/4.1.1/AppCenter-SDK-Apple-4.1.1.zip"],

third-party/flatc/BUILD

@@ -0,0 +1,37 @@
+
+genrule(
+    name = "flatc",
+    srcs = [
+        "@flatbuffers_zip//file",
+        "@cmake_tar_gz//file",
+    ],
+    cmd_bash =
+"""
+set -x
+    core_count=`PATH="$$PATH:/usr/sbin" sysctl -n hw.logicalcpu`
+    BUILD_DIR="$(RULEDIR)/build"
+    rm -rf "$$BUILD_DIR"
+    mkdir -p "$$BUILD_DIR"
+
+    CMAKE_DIR="$$(pwd)/$$BUILD_DIR/cmake"
+    rm -rf "$$CMAKE_DIR"
+    mkdir -p "$$CMAKE_DIR"
+    tar -xf "$(location @cmake_tar_gz//file)" -C "$$CMAKE_DIR"
+    
+    tar -xzf "$(location @flatbuffers_zip//file)" --directory "$$BUILD_DIR"
+    pushd "$$BUILD_DIR/flatbuffers-24.12.23"
+    mkdir build
+    cd build
+    PATH="$$PATH:$$CMAKE_DIR/cmake-3.23.1-macos-universal/CMake.app/Contents/bin" cmake .. -DCMAKE_BUILD_TYPE=Release"
+    make -j $$core_count
+    popd
+
+    tar -cf "$(location flatc.tar)" -C "$$BUILD_DIR/flatbuffers-24.12.23/build" .
+""",
+    outs = [
+        "flatc.tar",
+    ],
+    visibility = [
+        "//visibility:public",
+    ]
+)