git: openjdk/loom: fibers: Fix Windows build

[duke]

Changeset: 3be8a9bd
Author:    mgronlun <markus.gronlund at oracle.com>
Date:      2019-11-26 16:13:24 +0000
URL:       https://git.openjdk.java.net/loom/commit/3be8a9bd

Fix Windows build

! make/autoconf/flags-cflags.m4
! src/java.base/windows/classes/sun/nio/ch/NativeThread.java
! src/jdk.jdwp.agent/share/native/libjdwp/threadControl.c