Add documentation for the -sigopt option.

Reviewed-by: Paul Yang <yang.yang@baishancloud.com>
(Merged from #8520)

(cherry picked from commit d7b2124)

doc/man1/ca.pod

@@ -51,6 +51,7 @@ B<openssl> B<ca>
 [B<-engine id>]
 [B<-subj arg>]
 [B<-utf8>]
+[B<-sigopt nm:v>]
 [B<-create_serial>]
 [B<-rand_serial>]
 [B<-multivalue-rdn>]
@@ -134,6 +135,11 @@ The private key to sign requests with.
 The format of the data in the private key file.
 The default is PEM.
 
+=item B<-sigopt nm:v>
+
+Pass options to the signature algorithm during sign or verify operations.
+Names and values of these options are algorithm-specific.
+
 =item B<-key password>
 
 The password used to encrypt the private key. Since on some

doc/man1/dgst.pod

@@ -22,6 +22,7 @@ B<openssl dgst>
 [B<-verify filename>]
 [B<-prverify filename>]
 [B<-signature filename>]
+[B<-sigopt nm:v>]
 [B<-hmac key>]
 [B<-fips-fingerprint>]
 [B<-rand file...>]

doc/man1/req.pod

@@ -46,6 +46,7 @@ B<openssl> B<req>
 [B<-reqopt>]
 [B<-subject>]
 [B<-subj arg>]
+[B<-sigopt nm:v>]
 [B<-batch>]
 [B<-verbose>]
 [B<-engine id>]
@@ -82,6 +83,11 @@ This specifies the input filename to read a request from or standard input
 if this option is not specified. A request is only read if the creation
 options (B<-new> and B<-newkey>) are not specified.
 
+=item B<-sigopt nm:v>
+
+Pass options to the signature algorithm during sign or verify operations.
+Names and values of these options are algorithm-specific.
+
 =item B<-passin arg>
 
 The input file password source. For more information about the format of B<arg>
@@ -689,7 +695,7 @@ L<x509v3_config(5)>
 
 =head1 COPYRIGHT
 
-Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
 
 Licensed under the OpenSSL license (the "License").  You may not use
 this file except in compliance with the License.  You can obtain a copy

doc/man1/x509.pod

@@ -61,6 +61,7 @@ B<openssl> B<x509>
 [B<-clrext>]
 [B<-extfile filename>]
 [B<-extensions section>]
+[B<-sigopt nm:v>]
 [B<-rand file...>]
 [B<-writerand file>]
 [B<-engine id>]
@@ -366,6 +367,11 @@ If the input is a certificate request then a self signed certificate
 is created using the supplied private key using the subject name in
 the request.
 
+=item B<-sigopt nm:v>
+
+Pass options to the signature algorithm during sign or verify operations.
+Names and values of these options are algorithm-specific.
+
 =item B<-passin arg>
 
 The key password source. For more information about the format of B<arg>