fix(android): resolve two Windows build failures — bash path and CMake/Ninja absolute path

[kevinthelago]

Problem

Building the Android library on Windows fails in two distinct ways:

1. downloadPrebuiltBinaries — bash not found

Gradle calls commandLine 'bash' which on Windows resolves to C:\Windows\System32\bash.exe, the WSL relay. If WSL has no distro installed this throws:

execvpe(/bin/bash) failed: No such file or directory

Tracked in #1012.

2. buildCMakeDebug — Ninja cannot mkdir object directories

CMake/Ninja derives object file directories from absolute source paths. On Windows, Ninja converts the drive letter colon (C:) to an underscore (C_), producing:

CMakeFiles/react-native-audio-api.dir/C_/Users/.../audioapi

That path cannot be mkdir'd, so the build fails with:

ninja: error: mkdir(src/main/cpp/audioapi/CMakeFiles/react-native-audio-api.dir/C_/Users/...): No such file or directory

Tracked in #784.

Fix

android/build.gradle — detect Windows via Os.isFamily(Os.FAMILY_WINDOWS) and use Git Bash (C:\Program Files\Git\usr\bin\bash.exe) instead of the system bash. The Unix path remains unchanged.

android/src/main/cpp/audioapi/CMakeLists.txt — after globbing source files into *_ABS variables, convert each absolute path to a path relative to CMAKE_CURRENT_SOURCE_DIR using file(RELATIVE_PATH). Ninja then creates simple relative object directories with no drive letter, and the build proceeds normally.

Test plan

• Android build completes on Windows with Git for Windows installed
• Android build still works on macOS/Linux (Unix path unchanged)
• Prebuilt binaries download succeeds via Git Bash on Windows