Prevent error if move of [Makefile.build] already moved (pxscene#1651)

FitzerIRL · Michael Fiess · commit b4670faa8c9e · 2019-01-02T11:13:02.000-05:00
diff --git a/examples/pxScene2d/external/build.sh b/examples/pxScene2d/external/build.sh
@@ -148,7 +148,12 @@ if [ ! -e ./uWebSockets/libuWS.dylib ] ||
 then
 
   cd uWebSockets
-  mv Makefile.build Makefile
+
+  if [ -e Makefile.build ]
+  then
+    mv Makefile.build Makefile
+  fi
+
   make
   cd ..
 
