Fcntl - load the C Fcntl.h defines
This module is just a translation of the C fnctl.h file. Unlike the old mechanism of requiring a translated fnctl.ph file, this uses the h2xs program (see the Perl source distribution) and your native C compiler. This means that it has a far more likely chance of getting the numbers right.
#define symbols get translated; you must still correctly pack up your own arguments to pass as args for locking functions, etc.