set x permission on platform binary

build.php

@@ -136,6 +136,7 @@ if(!copy($OUTFILE, $OUTFILE2)){
     _abort("Could not copy $OUTFILE to $OUTFILE2");
 }
 _ok("file created: '$OUTFILE2'");
+_exec("chmod +x $OUTFILE2");
 
 _h1("Create readme");
 $readme="{$OUTFILE2}__README.md";