[ffigen] stabilize Objective-C availability and improve Windows environment robustness - #3133

[ffigen] stabilize Objective-C availability and improve Windows environment robustness#3133

YATIN072007 wants to merge 6 commits into

dart-lang:maindart-lang/native:mainfrom

YATIN072007:mainYATIN072007/native:mainCopy head branch name to clipboard