CDRIVER-1314: Use S_ISDIR() in stead of S_IFDIR
CDRIVER-1314: Use S_ISDIR() in stead of S_IFDIR

POSIX.1-1990 did not describe the S_IFMT, S_IFSOCK, S_IFLNK, S_IFREG,
S_IFBLK, S_IFDIR, S_IFCHR, S_IFIFO, S_ISVTX constants, but instead
demanded the use of the macros S_ISDIR(), and so on.  The S_IF*
constants are present in POSIX.1-2001 and later

mapr/libbson,rcsanchez97/libbson,paulmelnikow/libbson,ajdavis/libbson,mapr/libbson,mongodb/libbson,mongodb/libbson,alexeyvo/libbson,rcsanchez97/libbson,mongodb/libbson,ajdavis/libbson,paulmelnikow/libbson,rcsanchez97/libbson,alexeyvo/libbson,mapr/libbson,bjori/libbson,Convey-Compliance/libbson,alexeyvo/libbson,bjori/libbson,ajdavis/libbson,Convey-Compliance/libbson,bjori/libbson,paulmelnikow/libbson,paulmelnikow/libbson,paulmelnikow/libbson,Convey-Compliance/libbson