Update the info on version numbering

doc/crypto/OPENSSL_VERSION_NUMBER.pod

@@ -2,7 +2,7 @@
 
 =head1 NAME
 
-OPENSSL_VERSION_NUMBER, SSLeay - get OpenSSL version number
+OPENSSL_VERSION_NUMBER, SSLeay SSLeay_version - get OpenSSL version number
 
 =head1 SYNOPSIS
 
@@ -11,11 +11,27 @@ OPENSSL_VERSION_NUMBER, SSLeay - get OpenSSL version number
 
  #include <openssl/crypto.h>
  long SSLeay(void);
+ char *SSLeay_version(int t);
 
 =head1 DESCRIPTION
 
 OPENSSL_VERSION_NUMBER is a numeric release version identifier:
 
+ MMNNFFPPS: major minor fix patch status
+
+The status nibble has one of the values 0 for development, 1 to e for betas
+1 to 14, and f for release.
+
+for example
+
+ 0x000906000 == 0.9.6 dev
+ 0x000906023 == 0.9.6b beta 3
+ 0x00090605f == 0.9.6e release
+
+Versions prior to 0.9.3 have identifiers E<lt> 0x0930.
+Versions between 0.9.3 and 0.9.5 had a version identifier with this
+interpretation:
+
  MMNNFFRBB major minor fix final beta/patch
 
 for example
@@ -23,13 +39,39 @@ for example
  0x000904100 == 0.9.4 release
  0x000905000 == 0.9.5 dev
 
-Versions prior to 0.9.3 have identifiers E<lt> 0x0930.
+Version 0.9.5a had an interrim interpretation that is like the current one,
+except the patch level got the highest bit set, to keep continuity.  The
+number was therefore 0x0090581f.
+
+
 For backward compatibility, SSLEAY_VERSION_NUMBER is also defined.
 
 SSLeay() returns this number. The return value can be compared to the
 macro to make sure that the correct version of the library has been
 loaded, especially when using DLLs on Windows systems.
 
+SSLeay_version() returns different strings depending on B<t>:
+
+=over 4
+
+=item SSLEAY_VERSION
+The text variant of the version number and the release date.  For example,
+"OpenSSL 0.9.5a 1 Apr 2000".
+
+=item SSLEAY_CFLAGS
+The flags given to the C compiler when compiling OpenSSL are returned in a
+string.
+
+=item SSLEAY_PLATFORM
+The platform name used when OpenSSL was configured is returned.
+
+=back
+
+If the data request isn't available, a text saying that the information is
+not available is returned.
+
+For an unknown B<t>, the text "not available" is returned.
+
 =head1 RETURN VALUE
 
 The version number.