opensslconf.h always expects HEADER_... (no leading underscore).

Submitted by: Andy Polyakov <appro@fy.chalmers.se>

(problems with BN_LLONG have been reported both for hpux-cc
and for hpux10-gcc).

Submitted by: Jeon KyoungHo <khjeon@sds.samsung.co.kr>

to use 'void *' rather than 'char *' for an "arbitrary extension".

Submitted by: Andreas Ley <andy@rz.uni-karlsruhe.de

the the PBE code and a new constant PKCS5_DEFAULT_ITER for the default
iteration count if it is passed as zero.

_directory_ in $PATH was also accepted as the interpreter.

Submitted by: Andy Polyakov <appro@fy.chalmers.se>

Submitted by: Eric Ding <ericding@MIT.EDU>

should make modifying them easier.

Fix the selfsign demo: it was rather ancient and used deleted functions.

duplicated in cbc_enc.c (without IV updating) and in des_enc.c

As pointed out by others on the openssl-dev list, des_cbc_encrypt (without
IV updating; defined in cbc_enc.c) exists only for historical reasons:
des_ncbc_encrypt should be used instead (and the caller does not have
to manually update the IV).

If des_cbc_enrypt is not needed for backwards compatibility, the
definition of des_ncbc_encrypt should be put back into des_enc.c, and
both cbc_enc.c and ncbc_enc.c can be deleted.

If des_cbc_encrypt *is* needed for backwards compatibility, its behaviour
obviously should not change (i.e., don't add IV updating).

Pointed out by: Janez Jere <jj@void.si>

Allow configuring the name of that header file.