[backport] [DEPENDS] Remove the facilities for building win32
It is no longer supported, so remove the facilities used to build it and remove it from the build-all target. Note: openssl and boost still have configurations for it, I leave them as they don't hurt and are also still present on core.
Test Plan:
Obtain the MacOS10.14.sdk.tar.xz that as described in doc/gitian-building.md
cd depends
mkdir SDKs
tar -C SDKs -xf /path/to/MacOS10.14.sdk.tar.xz
make build-all
Differential Revision: https://reviews.bitcoinabc.org/D6056
Edited by freetrader