RFR: 8276672: Cannot build hsdis on WSL [v3]

[Yasumasa Suenaga]

> JDK-8275128 introduced new Makefile for hsdis to integrate it to normal build system, however it does not work on WSL 1 Ubuntu 20.04 and MinGW from Ubuntu.
> 
> Hsdis.gmk has two problems:
> 
> 1. MinGW version is fixed to "9.2.0"
> 2. Assumes sysroot for MinGW is located at /usr/$MINGW_BASE/sys-root
> 
> I tested this change on WSL only, so it is appreciate to review on Cygwin.

Yasumasa Suenaga has updated the pull request incrementally with one additional commit since the last revision:

  Remove SYSROOT_FLAGS

-------------

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6269/files
  - new: https://git.openjdk.java.net/jdk/pull/6269/files/7fa765cd..0eaf388a

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6269&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6269&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6269.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6269/head:pull/6269

PR: https://git.openjdk.java.net/jdk/pull/6269