Document OPENSSL_VERSION_TEXT macro

This commit documents the OPENSSL_VERSION_TEXT which is currently
missing in the man page.
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NRichard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/7301)

(cherry picked from commit 7c69495712e3dc9aa8db38271f0c3faeb2037165)

doc/man3/OPENSSL_VERSION_NUMBER.pod

@@ -2,13 +2,14 @@
 
 =head1 NAME
 
-OPENSSL_VERSION_NUMBER, OpenSSL_version,
+OPENSSL_VERSION_NUMBER, OPENSSL_VERSION_TEXT, OpenSSL_version,
 OpenSSL_version_num - get OpenSSL version number
 
 =head1 SYNOPSIS
 
  #include <openssl/opensslv.h>
  #define OPENSSL_VERSION_NUMBER 0xnnnnnnnnnL
+ #define OPENSSL_VERSION_TEXT "OpenSSL x.y.z xx XXX xxxx"
 
  #include <openssl/crypto.h>
 
@@ -45,6 +46,10 @@ Version 0.9.5a had an interim interpretation that is like the current one,
 except the patch level got the highest bit set, to keep continuity.  The
 number was therefore 0x0090581f.
 
+OPENSSL_VERSION_TEXT is the text variant of the version number and the
+release date.  For example,
+"OpenSSL 1.0.1a 15 Oct 2015".
+
 OpenSSL_version_num() returns the version number.
 
 OpenSSL_version() returns different strings depending on B<t>:

util/private.num

@@ -241,6 +241,7 @@ EVP_seed_cfb                            define
 EVP_sm4_cfb                             define
 OBJ_cleanup                             define deprecated 1.1.0
 OPENSSL_VERSION_NUMBER                  define
+OPENSSL_VERSION_TEXT                    define
 OPENSSL_clear_free                      define
 OPENSSL_clear_realloc                   define
 OPENSSL_free                            define