/usr/lib/gcc/ is in gobjc-mingw-w64-x86-64 6.3.0-18+19.3+b3.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/gcc/x86_64-w64-mingw32/
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/cc1obj
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/NXConstStr.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/Object.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/Protocol.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/message.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/objc-decls.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/objc-exception.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/objc-sync.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/objc.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/runtime.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/include/objc/thr.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/libobjc-4.dll
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/libobjc.a
/usr/lib/gcc/x86_64-w64-mingw32/6.3-posix/libobjc.dll.a
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/cc1obj
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/NXConstStr.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/Object.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/Protocol.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/message.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/objc-decls.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/objc-exception.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/objc-sync.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/objc.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/runtime.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/include/objc/thr.h
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/libobjc-4.dll
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/libobjc.a
/usr/lib/gcc/x86_64-w64-mingw32/6.3-win32/libobjc.dll.a