~/Downloads clang -Wall -dynamiclib -o flip.dylib flip.c -framework IOKit -arch i386 -arch x86_64
ld: warning: The i386 architecture is deprecated for macOS (remove from the Xcode build setting: ARCHS)
ld: warning: ignoring file /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks//IOKit.framework/IOKit.tbd, missing required architecture i386 in file /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks//IOKit.framework/IOKit.tbd
ld: warning: ignoring file /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/libSystem.tbd, missing required architecture i386 in file /Applications/Xcode-beta.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/lib/libSystem.tbd
Undefined symbols for architecture i386:
  "_IOConnectCallMethod", referenced from:
      _fake_IOConnectCallMethod in flip-1c8052.o
      _interposers in flip-1c8052.o
     (maybe you meant: _fake_IOConnectCallMethod)
  "_rand", referenced from:
      _maybe in flip-1c8052.o
      _flip_bit in flip-1c8052.o
  "_srand", referenced from:
      _maybe in flip-1c8052.o
  "_time", referenced from:
      _maybe in flip-1c8052.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)