* filedoalloc.c (_POSIX_SOURCE): Remove definition.
        * fileops.c (_POSIX_SOURCE): Likewise.
        * iopopen.c (_POSIX_SOURCE): Likewise.
        * procbuf.cc (_POSIX_SOURCE): Likewise.
        * libioP.h (_POSIX_SOURCE): And define it here.
        * stdiostream.cc: Include libioP.h before others.

From-SVN: r26380