Error happen when include STL header

[for-just-we]

Hi, author!
I recently work on implement new libtool based on clang-API, and I work on MacOSX-arm64 now, my environment is: LLVM version is 12.0.0, when I analyze a c++ code containing include<iostream>, libtool report error /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/wchar.h:89:10: fatal error: 'stdarg.h' file not found. But clang could normally analyze this code. And there is stdarg.h in LLVM header search path, what should I do to fix this.