4.2 source compatibility

[Steve Summit]

I really like to try to keep my source code generic, with the
occasional machine/compiler/operating dependencies handled with
#ifdef's.  This is more-or-less possible in all cases I have come
across except for the stupid .h files that moved under 4.2.  (I
refer specifically to time.h and ndir.h .)  It simply isn't
possible to take the same file to a 4.2 machine and a non-4.2
machine and compile it without change.  I've been using -DBSD42
on the cc line, and putting it in CFLAGS in my makefiles, which
keeps the .c files generic, but requires me to keep different
makefiles on the different machines.

A PLEA TO BERKELEY (but it's probably too late for 4.3):
Please please please predefine some symbol or other in 4.2 and
later cpp's.  It would make life _s_o much easier...

                                         Steve Summit
                                         tektronix!bronze!stevesu