Improve javah's error message.

PR: 8095
Submitted by:	Jesse Glick <jesse.glick@netbeans.com>


git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@272513 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/optional/Javah.java

@@ -325,7 +325,7 @@ public class Javah extends Task {
             if (ex instanceof BuildException) {
                 throw (BuildException) ex;
             } else {
-                throw new BuildException("Error starting javah: ", ex, location);
+                throw new BuildException("Error starting javah: " + ex, ex, location);
             }
         }
     }