The user.dir trick doesn't seem to work on OS X anymore, PR 23400

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@275359 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/Execute.java

@@ -124,7 +124,7 @@ public class Execute {
             // Ignore and keep trying
         }
 
-        if (Os.isFamily("mac")) {
+        if (Os.isFamily("mac") && !Os.isFamily("unix")) {
             // Mac
             shellLauncher = new MacCommandLauncher(new CommandLauncher());
         } else if (Os.isFamily("os/2")) {