hg: jdk/submit: 8248526: configure script failed on WSL in May 2020 update

[suenaga at oss.nttdata.com]

Changeset: edeb0d435a35
Author:    ysuenaga
Date:      2020-07-01 07:23 +0900
URL:       https://hg.openjdk.java.net/jdk/submit/rev/edeb0d435a35

8248526: configure script failed on WSL in May 2020 update
Reviewed-by: ihse

! make/autoconf/basic_windows.m4
! make/autoconf/util_windows.m4
! make/src/native/fixpath.c