+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]