Tsss, SSLeay_version() was already documented, it just was not linked in.

=head1 NAME

OPENSSL_VERSION_NUMBER, SSLeay SSLeay_version - get OpenSSL version number

OPENSSL_VERSION_NUMBER, SSLeay, SSLeay_version - get OpenSSL version number

=head1 SYNOPSIS

 #include <openssl/crypto.h>

 long SSLeay(void);

 char *SSLeay_version(int t);

 const char *SSLeay_version(int t);

=head1 DESCRIPTION

=pod

=head1 NAME

SSLeay_version - retrieve version/build information about OpenSSL library

=head1 SYNOPSIS

 #include <openssl/crypto.h>

 const char *SSLeay_version(int type);

=head1 DESCRIPTION

SSLeay_version() returns a pointer to a constant string describing the

version of the OpenSSL library or giving information about the library

build.

The following B<type> values are supported:

=over 4

=item SSLEAY_VERSION

The version of the OpenSSL library including the release date.

=item SSLEAY_CFLAGS

The compiler flags set for the compilation process in the form

"compiler: ..."  if available or "compiler: information not available"

otherwise.

=item SSLEAY_BUILT_ON

The date of the build process in the form "built on: ..." if available

or "built on: date not available" otherwise.

=item SSLEAY_PLATFORM

The "Configure" target of the library build in the form "platform: ..."

if available or "platform: information not available" otherwise.

=back

=head1 RETURN VALUES

The following return values can occur:

=over 4

=item "not available"

An invalid value for B<type> was given.

=item Pointer to constant string

Textual description.

=back

=head1 SEE ALSO

L<crypto(3)|crypto(3)>

=cut

=item AUXILIARY FUNCTIONS

L<err(3)|err(3)>, L<threads(3)|threads(3)>, L<rand(3)|rand(3)>,

L<SSLeay_version(3)|SSLeay_version(3)>

L<OPENSSL_VERSION_NUMBER(3)|OPENSSL_VERSION_NUMBER(3)>

=item INPUT/OUTPUT, DATA ENCODING