MSYS2: Don't compile with dynamic base

A executable compiled under MSYS2 mingw32 is compiled with dynamicbase by default, which drmingw doesn't support fully. And reports the assumed load address instead of the actual load address. Making it impossible to resolve a EIP to file. This fixes that by appending -Wl,--disable-dynamicbase to the linker flags if supported.

Check could probably be more generic, but I don't know if any other version of mingw-w64 provides a version of binutils new enough to support said flag, plus I think other platforms will be fine.

Resolves #671 (closed)