Added a check for macOS 11 and newer to resolve a compile error:
*** Unexpected product version 11.2.

Added Internals::getcwd.
Fallback to the built-in getcwd to resolve compile errors on macOS:
Can't locate Errno.pm in @INC
/miniperl not found

Signed-off-by: Georgi Valkov <gvalkov@abv.bg>