Do not merge: AsMain: run working HelloWorld asm example for iOS, since I don't have a DTK

[zhuowei]

My other PRs should get AsMain working. I don't have a DTK, so I tested these changes by sideloading it to an iPad:

• add these patches
• make
• Create a new Xcode project named HelloWorld
• in Build Phases->Compile Sources, delete everthing
• drag HelloWorld into the project
• Clean build folder, build.
• Make sure the app that's build has the right HelloWorld file.
• Clean build folder, run.

Xcode displays "Hello World!" in the console.

I'm guessing that, since macOS on ARM and iOS are very similar, the alignment change should just work on macOS.