_PC_ASYNC_IO      903 ext/etc/constdefs.h #if !defined(_PC_ASYNC_IO)
_PC_ASYNC_IO      905 ext/etc/constdefs.h #  define _PC_ASYNC_IO _PC_ASYNC_IO
_PC_ASYNC_IO     1481 ext/etc/constdefs.h #if defined(_PC_ASYNC_IO)
_PC_ASYNC_IO     1482 ext/etc/constdefs.h     rb_define_const(mod, "PC_ASYNC_IO", INTEGER2NUM(_PC_ASYNC_IO));