Adding support for a custom target dir while building, fixing a few issues...

Adding support for a custom target dir while building, fixing a few issues where the SITE.ipc folder/file was not created for a fresh build. Also adding check to the run script that tries to detect if we are doing a first build, and compensate for the first failure.

src/epics/util/lib/IPCx.pm

@@ -221,7 +221,7 @@ sub frontEndCode {
 
     for ($k = 0; $k < $::ipcxCnt; $k++) {
         if ($::ipcxRef[$k] == $i) {
-            index = $k;
+            $index = $k;
             last;
         }
     }