Update win32/install-msvc.mak, win32/config-msvc.mak.in

This PR resolves some issues related to the build process on Windows, specifically those related to path escaping and missing includes. Additionally, it removes the need for a PYTHON prefix, by inferring it from the system environment variables instead. This change is due to the previous prefix not functioning correctly and adding unnecessary steps in the build process involving finding Python location and pasting it manually.

Fix: #954 (closed)