add Berkeley specific headers

SCCS-vsn: usr.bin/tn3270/sys_curses/makefile 3.2
SCCS-vsn: usr.bin/tn3270/sys_curses/system.c 3.3
SCCS-vsn: usr.bin/tn3270/sys_curses/terminal.h 3.2
SCCS-vsn: usr.bin/tn3270/sys_curses/termout.c 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkhits/dohits.c 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkhits/dohits.h 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkdctype/ectype.c 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkdctype/ectype.h 3.2
SCCS-vsn: usr.bin/tn3270/tools/makefile 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkastods/mkastods.c 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkastosc/mkastosc.c 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkdctype/mkdctype.c 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkdstoas/mkdstoas.c 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkhits/mkhits.c 3.2
SCCS-vsn: usr.bin/tn3270/tools/mkmake.y 1.18
SCCS-vsn: usr.bin/tn3270/tools/prt3270.c 3.3
SCCS-vsn: usr.bin/tn3270/distribution/utilities/makefile 3.2
SCCS-vsn: usr.bin/tn3270/distribution/utilities/tncomp.h 3.2
SCCS-vsn: usr.bin/tn3270/distribution/utilities/tnrecv.c 3.2