add isastream (obsolete STREAMS junk) apparently some packages see stropts.h and want to be able to use this. the implementation checks that the file descriptor is valid by using fcntl/F_GETFD so it can report an error if not (as specified).
fill in junk in stropts.h STREAMS are utterly useless as far as I can tell, but some software was apparently broken by the presence of stropts.h but lack of macros it's supposed to define...
initial check-in, version 0.5.0