gpgtar: Add dummy option --tar

--
GnuPG-bug-id: 3772

Signed-off-by: Werner Koch <wk@gnupg.org>

doc/tools.texi

@@ -2127,6 +2127,11 @@ and parse them.  The only supported tar options are "--directory",
 "--files-from", and "--null" This is an obsolete options because those
 supported tar options can also be given directly.
 
+@item --tar @var{command}
+@opindex tar
+This is a dummy option for backward compatibility.
+@c ... to the gpg-zip script we provided in the past
+
 @item --version
 @opindex version
 Print version of the program and exit.

tools/gpgtar.c

@@ -79,6 +79,7 @@ enum cmd_and_opt_values
     /* Compatibility with gpg-zip.  */
     oGpgArgs,
     oTarArgs,
+    oTarProgram,
 
     /* Debugging.  */
     oDryRun,
@@ -122,6 +123,7 @@ static gpgrt_opt_t opts[] = {
 
   ARGPARSE_s_s (oGpgArgs, "gpg-args", "@"),
   ARGPARSE_s_s (oTarArgs, "tar-args", "@"),
+  ARGPARSE_s_s (oTarProgram, "tar", "@"),
 
   ARGPARSE_end ()
 };
@@ -381,6 +383,9 @@ parse_arguments (gpgrt_argparse_t *pargs, gpgrt_opt_t *popts)
           }
           break;
 
+        case oTarProgram:  /* Dummy option.  */
+          break;
+
         case oTarArgs:
           {
             int tar_argc;
@@ -414,6 +419,7 @@ parse_arguments (gpgrt_argparse_t *pargs, gpgrt_opt_t *popts)
     }
 }
 
+
 
 /* gpgtar main. */
 int