Rebuild mingw-w64 for winpthreads
Depends on D7402.
It also completely builds mingw-w64
Signed-off-by: Martin Reboredo <email@example.com>
Test Plan: Built and tested (in Wine) a C "Hello, World!" program (with both GCC and Clang), a libstdc++ test, the godot export template, a simple Rust cross-compilation "Hello, World!" app and a Go cross-compiled sdl2 program (which also required a locally built SDL2 package).
Reviewers: Triage Team, DataDrake
Reviewed By: Triage Team, DataDrake
Differential Revision: https://dev.getsol.us/D8442