Depends-on:
fcntl-h
extensions
+close [test $HAVE_FCNTL = 0 || test $REPLACE_FCNTL = 1]
dup2 [test $HAVE_FCNTL = 0 || test $REPLACE_FCNTL = 1]
getdtablesize [test $HAVE_FCNTL = 0 || test $REPLACE_FCNTL = 1]
msvc-nothrow [test $HAVE_FCNTL = 0 || test $REPLACE_FCNTL = 1]