[debugserver] Fix OSX build for older XCode versions after r251091.

[dawn]

Summary

svn r251091 introduced references to LC_VERSION_MIN_TVOS and LC_VERSION_MIN_WATCHOS which aren't defined in XCode versions older than 7. This patch fixes the build by skipping the code if TARGET_OS_TV or TARGET_OS_WATCH aren't defined.

[jasonmolenda]

Thanks, I was trying to spot problems like this but missed this one.

tools/debugserver/source/RNBRemote.cpp

                     DNBLogThreadedIf (LOG_RNB_PROC, "LC_VERSION_MIN_MACOSX -> 'ostype:macosx;'");
                     break;
 
+#if defined (TARGET_OS_TV) && TARGET_OS_TV == 1
                 case LC_VERSION_MIN_TVOS:
                     os_handled = true;
                     rep << "ostype:tvos;";
                     DNBLogThreadedIf (LOG_RNB_PROC, "LC_VERSION_MIN_TVOS -> 'ostype:tvos;'");
                     break;
+#endif
 
+#if defined (TARGET_OS_WATCH) && TARGET_OS_WATCH == 1
                 case LC_VERSION_MIN_WATCHOS:
                     os_handled = true;
                     rep << "ostype:watchos;";
                     DNBLogThreadedIf (LOG_RNB_PROC, "LC_VERSION_MIN_WATCHOS -> 'ostype:watchos;'");
                     break;
+#endif
 
                 default:
                     break;