Add support for building on Windows

[mike-myers-tob]

Funny enough, it looks like my Windows build system had bfd and libiberty headers and library dependencies in C:\Strawberry\c\include and C:\Strawberry\c\lib\ so these pre-requisites can be satisfied by installing Strawberry Perl.

Developers can choco install the packages for git cmake ninja doxygen.install graphviz etc and get everything else needed.

When building, though, we need to set the _WINDOWS and _WIN64 compile-time definitions, so that all the conditional compilation preprocessor statements in the Ghidra headers will work.