8f32b345de
gcc 7.[1,2] (at least) fails to correctly parse the OSX 10.13 sys/syslog.h header. As a results we need to potect syslog support in OPAL, PMIX and ORTE. Signed-off-by: George Bosilca <bosilca@icl.utk.edu> Signed-off-by: Jeff Squyres <jsquyres@cisco.com>