[llvm] [lipo] Support creating Universal 64 bit Mach-O files. (PR #67737)

[Daniel Rodríguez Troitiño via llvm-commits]

drodriguez wrote:

Sorry. I was trying to get the MSan working on my machine. It seems to do many builds before giving me any error.

I think your fix is the right thing. That `reserved` field seems uninitialized and I did not see the difference between the two different headers when I was changing the code. Thanks for fixing.

Sorry for any breakage I might have caused. I will try to be more careful in the future.

https://github.com/llvm/llvm-project/pull/67737