Please try this patch, I can't. It's split up for readability. Replace defined(BSD) in 1st patch with defined(__BSD__) or whatever, see below.

http://folk.uio.no/hbf/its7363-cleanup.txt

Also, maybe we can drop __APPLE__ - it may #define __BSD__ too. ANDROID should be something like __ANDROID__. I can't test either.

Explanation:

defined(BSD) breaks in strict ISO C mode. Is there a symbol like __BSD__ or __BSD to use instead?

Namespace-wise, "MDB_USE_POSIX_SEM" would be better.

MDB_FDATASYNC should not depend on USE_POSIX_SEM.

We can #ifndef PTHREAD_PROCESS_SHARED instead of BSD, unless someone #define it without supporting it. Not for MDB_FDATASYNC though.