msys2Path property
MSYS2 installation root (e.g. r'D:\msys2'), used only when
compiler is WindowsCompiler.msys2Clang or
WindowsCompiler.msys2Gcc.
When null (default), the builder resolves the root from the
MSYS2_ROOT environment variable, then probes well-known install
locations (C:\msys64, C:\msys2, D:\msys2). The toolchain is
expected at <root>\ucrt64\bin\clang(++).exe (msys2Clang) or
<root>\ucrt64\bin\gcc(++).exe (msys2Gcc).
Implementation
final String? msys2Path;