add comments.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@39183 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/socket/extconf.rb

@@ -114,20 +114,20 @@ EOS
 end
 
 if have_struct_member("struct sockaddr_in", "sin_len", headers)
-  $defs[-1] = "-DHAVE_SIN_LEN"
+  $defs[-1] = "-DHAVE_SIN_LEN" # change from -DHAVE_ST_SIN_LEN.
 end
 
 #   doug's fix, NOW add -Dss_family... only if required!
 doug = proc {have_struct_member("struct sockaddr_storage", "ss_family", headers)}
 if (doug[] or
     with_cppflags($CPPFLAGS + " -Dss_family=__ss_family", &doug))
-  $defs[-1] = "-DHAVE_SOCKADDR_STORAGE"
+  $defs[-1] = "-DHAVE_SOCKADDR_STORAGE" # change from -DHAVE_ST_SS_FAMILY.
   doug = proc {have_struct_member("struct sockaddr_storage", "ss_len", headers)}
   doug[] or with_cppflags($CPPFLAGS + " -Dss_len=__ss_len", &doug)
 end
 
 if have_struct_member("struct sockaddr", "sa_len", headers)
-  $defs[-1] = "-DHAVE_SA_LEN "
+  $defs[-1] = "-DHAVE_SA_LEN " # change from -DHAVE_ST_SA_LEN.
 end
 
 if !have_macro("IPPROTO_IPV6", headers) && have_const("IPPROTO_IPV6", headers)