vlc.git will now target macOS 10.10 or higher, therefore some
symbols can be enabled now, as they are available.

The full list of dropped symbols with their minimum version is:
- export ac_cv_func_ffsll=no # 10.9 / ios7
- export ac_cv_func_flsll=no # 10.9 / ios7
- export ac_cv_func_fdopendir=no # 10.10 / ios8
- export ac_cv_func_openat=no # 10.10 / ios8
- export ac_cv_func_fstatat=no # 10.10 / ios8
- export ac_cv_func_readlinkat=no # 10.10 / ios8