DAP: support to show global variables

Author: ko1

lib/debug/server_dap.rb

@@ -540,8 +540,8 @@ def process_protocol_request req
         if ref = @var_map[varid]
           case ref[0]
           when :globals
-            vars = global_variables.map do |name|
-              gv = 'Not implemented yet...'
+            vars = global_variables.sort.map do |name|
+              gv = eval(name.to_s)
               {
                 name: name,
                 value: gv.inspect,