A perl module to parse through C headers

OpenSSL::ParseC is a module that parses through a C header file and
returns a list with information on what it found.  Currently, the
information it returns covers function and variable declarations,
macro definitions, struct declarations/definitions and typedef
definitions.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7191)