test/os/mac/pkgconfig_spec: fix libffi detection on 12.3+ SDK
test/os/mac/pkgconfig_spec: fix libffi detection on 12.3+ SDK

Homebrew/brew,nandub/brew,Homebrew/brew,JCount/brew,nandub/brew,JCount/brew,nandub/brew,MikeMcQuaid/brew,JCount/brew,JCount/brew,MikeMcQuaid/brew,Homebrew/brew,MikeMcQuaid/brew,nandub/brew,Homebrew/brew,MikeMcQuaid/brew