8087577: Fix host OS check with refactoring

[Andre Queiroz]

Hi,

I've tried JFX cross building (Windows > Android; Linux > Android) and
things got wrong, mainly on Windows. The build script tried to build native
Windows libraries instead only Android native libraries.

I'm working on a refactoring of the build script. There is a lot of work
but, also, a lot to learn. I appreciate comments and tips for this work,
initially on how to easily debug build script (watch execution steps and
variables).

Regards,

André Queiroz
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.org/pipermail/openjfx-dev/attachments/20220803/3853c4b4/attachment.htm>