hg: jdk/sandbox: Lots of cleanup. Compiles on cygwin.

[magnus.ihse.bursie at oracle.com]

Changeset: f7ac60afb3e9
Author:    ihse
Date:      2020-07-02 02:06 +0200
URL:       https://hg.openjdk.java.net/jdk/sandbox/rev/f7ac60afb3e9

Lots of cleanup. Compiles on cygwin.

! make/autoconf/basic.m4
! make/autoconf/basic_windows.m4
! make/autoconf/compare.sh.in
! make/autoconf/help.m4
! make/autoconf/spec.gmk.in
! make/autoconf/toolchain.m4
! make/autoconf/toolchain_microsoft.m4
! make/scripts/fixpath.sh