[win][mingw-w64] MinGW builds

[Guillaume Vara]

Hello crashpad team :) I've been working on a fork of Crashpad (https://github.com/getsentry/crashpad/tree/getsentry) to allow MinGW builds. The whole issue with the ASM_MASM building has been fixed using uasm (https://github.com/Terraspace/UASM) as an external dependency. I also had to update a few of the original files to achieve building : I was wondering if you guys could check my modifications and maybe implement them in the upstream depository ? I am ready to help so do not hesitate to ask !

[Acid Tonic]

Hey was curious if this got upstreamed or not? I am looking to use with mingw on windows.