The new files libc-config.h and cdefs.h, break MSVC in several ways: 1) libc-config.h: # undef __inline
'__inline' is a built-in reserved word used through-out the MS SDK. 2) MSVC doesn't accept this: #define libc_hidden_proto(name, attrs...) Why not simply? #define libc_hidden_proto(name, ...) -- --gv