Apart from public and internal header files, there is a third type called
local header files, which are located next to source files in the source
directory. Currently, they have different suffixes like

  '*_lcl.h', '*_local.h', or '*_int.h'

This commit changes the different suffixes to '*_local.h' uniformly.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9681)

Removed e_os.h from all bar three headers (apps/apps.h crypto/bio/bio_lcl.h and
ssl/ssl_locl.h).

Added e_os.h into the files that need it now.

Directly reference internal/nelem.h when required.
Reviewed-by: NAndy Polyakov <appro@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/4188)

Reviewed-by: NRichard Levitte <levitte@openssl.org>

Add copyright to most .pl files
This does NOT cover any .pl file that has other copyright in it.
Most of those are Andy's but some are public domain.
Fix typo's in some existing files.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Don't have #error statements in header files, but instead wrap
the contents of that file in #ifndef OPENSSL_NO_xxx
This means it is now always safe to include the header file.
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Reviewed-by: NViktor Dukhovni <viktor@openssl.org>

They are not numbers in the machine byte order.
Reviewed-by: NAndy Polyakov <appro@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

Reviewed-by: NAndy Polyakov <appro@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

Reviewed-by: NAndy Polyakov <appro@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>