* regtool.cc (KEY_WOW64_64KEY): Define.

(longopts): Add --wow64 option.
	(opts): Add -w option.
	(wow64): New variable to control usage of KEY_WOW64_64KEY access flag.
	(usage): Add text for --wow64/-w option.
	(print_version): Fix copyright.
	(find_key): Use wow64 value in calls to RegOpenKeyEx and RegCreateKeyEx.
	(cmd_add): Use wow64 value in call to RegCreateKeyEx.
	(regDeleteKeyEx): New function pointer to load RegDeleteKeyEx function
	dynamically.
	(cmd_remove): Load and use regDeleteKeyEx when wow64 is set.
	(main): Handle --wow64/-w option.
	* utils.sgml: Document the new -w option.

winsup/utils/utils.sgml

@@ -1060,6 +1060,7 @@ Other Options:
  -h, --help     output usage information and exit
  -q, --quiet    no error output, just nonzero return if KEY/VALUE missing
  -v, --verbose  verbose output, including VALUE contents when applicable
+ -w, --wow64    access 64 bit registry view (ignored on 32 bit Windows)
  -V, --version  output version information and exit
 
 KEY is in the format [host]\prefix\KEY\KEY\VALUE, where host is optional
@@ -1086,6 +1087,15 @@ Conversely, the <literal>-q</literal> option supresses error messages,
 so you can use the exit status of the program to detect if a key
 exists or not (for example).</para>
 
+<para>The <literal>-w</literal> option allows to access the 64 bit view
+on the registry.  Several subkeys exist in a 32 bit and a 64 bit version
+when running on Windows 64.  Since Cygwin is running in 32 bit mode, it
+has only access to the 32 bit view of these registry keys.  When using
+the <literal>-w</literal> the 64 bit view is used and
+<command>regtool</command> can access the entire registry.
+This option is simply ignored when running on 32 bit Windows versions.
+</para>
+
 <para>You must provide <command>regtool</command> with an 
 <emphasis>action</emphasis> following options (if any). Currently,
 the action must be <literal>add</literal>, <literal>set</literal>,