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DESCRIBE THE ISSUE IN DETAIL:

I'm trying to use NDK to build a C++ Android app. I have the latest Android Studio and am running on Windows 11. My goal is to install and use a newer CMake and Ninja, because I want to use C++20 modules.

I follow the instructions here, and installed a newer copy of CMake that what came with the NDK. There are 4 steps documented in that link. 1-3 work fine. But 4 does not. I need to install a newer Ninja. I did that, and I added it to my PATH environment variable. However Android Studio's build process does not pick it up. I get build errors like this:

C++ build system [configure] failed while executing:
   @echo off
   "C:\\Program Files\\CMake\\bin\\cmake.exe" ^
   ...
   "-DCMAKE_MAKE_PROGRAM=C:\\Users\\rob\\AppData\\Local\\Android\\Sdk\\cmake\\3.22.1\\bin\\ninja.exe" ^
   ...
The Ninja generator does not support C++20 modules using Ninja version
    1.10.2

Despite the fact that I can run the correct ninja from my Powershell:

PS C:\Users\rob> ninja --version
1.11.1

This function findNinjaPathLogic does not appear to use the Ninja on my path.

I think what we need is a way to set the Ninja path in the gradle configuration.

STEPS TO REPRODUCE:

1. Create a new Native C++ Project
2. Upgrade to the latest NDK (26.2.11394342)
3. Set ndkVersion in the build.gradle.kts file
   android {
   ndkVersion = "26.2.11394342"
   ...
4. Install a new CMake. I did 3.29.0-rc1.
5. Set its path in local.properties
   cmake.dir=C:\Program Files\CMake
6. Set its version in build.gradle.kts
   android { ... externalNativeBuild { cmake { ... version = "3.29.0-rc1"
7. Install latest Ninja
8. Add it to the Path environment variable on your system.
9. Add a foo.cpp file to use modules as shown below.
10. Setup the C++ modules in the CMake file as shown below.
11. Try to build project in Android Studio. You will see errors like the one above.

foo.cpp

module;
export module foo;
export int foo_func(int a) {
    return a + 1;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.29.0)
project("hellotriangle")
set(CMAKE_CXX_STANDARD, 23)
add_library(${CMAKE_PROJECT_NAME} SHARED)
target_sources(${CMAKE_PROJECT_NAME} PRIVATE
    FILE_SET all_my_modules TYPE CXX_MODULES
    FILES foo.cpp
        )
target_sources(${CMAKE_PROJECT_NAME} PRIVATE
        native-lib.cpp)

target_link_libraries(${CMAKE_PROJECT_NAME}
        android
        log)

Studio Build: Android Studio Hedgehog | 2023.1.1 Patch 1
Build #AI-231.9392.1.2311.11255304, built on December 26, 2023
Runtime version: 17.0.7+0-b2043.56-10550314 amd64
VM: OpenJDK 64-Bit Server VM by JetBrains s.r.o.
Windows 11.0
GC: G1 Young Generation, G1 Old Generation
Memory: 2048M
Cores: 20
Registry:
external.system.auto.import.disabled=true
debugger.new.tool.window.layout=true
ide.text.editor.with.preview.show.floating.toolbar=false
ide.experimental.ui=true
Version of Gradle Plugin: 8.2.1
Version of Gradle: 8.2
NDK: 26.2.11394342
Version of Java: 17
OS: Windows 11