goto-diff: reinstate --show-properties

This was wrongly removed in 3d8b0cd as the show-properties option
is used to control goto-diff's default output. (This use of
show-properties is quite different from the support in other cbmc or
goto-instrument.)

Author: tautschnig

src/goto-diff/goto_diff_parse_options.cpp

@@ -64,6 +64,8 @@ void goto_diff_parse_optionst::get_command_line_options(optionst &options)
   // all checks supported by goto_check
   PARSE_OPTIONS_GOTO_CHECK(cmdline, options);
 
+  options.set_option("show-properties", cmdline.isset("show-properties"));
+
   // Options for process_goto_program
   options.set_option("rewrite-union", true);
 }
@@ -224,6 +226,7 @@ void goto_diff_parse_optionst::help()
     "\n"
     "Diff options:\n"
     HELP_SHOW_GOTO_FUNCTIONS
+    HELP_SHOW_PROPERTIES
     " --show-loops                 show the loops in the programs\n"
     " -u | --unified               output unified diff\n"
     " --change-impact | \n"

src/goto-diff/goto_diff_parse_options.h

@@ -30,6 +30,7 @@ class optionst;
 #define GOTO_DIFF_OPTIONS \
   "(json-ui)" \
   OPT_SHOW_GOTO_FUNCTIONS \
+  OPT_SHOW_PROPERTIES \
   "(show-loops)" \
   OPT_GOTO_CHECK \
   OPT_COVER \