return to the original find syntax (newsyntax.c -> main.c, delete

return to the original find syntax (newsyntax.c -> main.c, delete
oldsyntax.c; create extern.h for ANSI prototypes; create true error routine;
make NEW macro a real routine

SCCS-vsn: usr.bin/find/Makefile 5.2
SCCS-vsn: usr.bin/find/find.1 6.23
SCCS-vsn: usr.bin/find/find.c 5.2
SCCS-vsn: usr.bin/find/find.h 5.8
SCCS-vsn: usr.bin/find/function.c 5.16
SCCS-vsn: usr.bin/find/main.c 5.8
SCCS-vsn: usr.bin/find/misc.c 5.8
SCCS-vsn: usr.bin/find/operator.c 5.4
SCCS-vsn: usr.bin/find/option.c 5.7