java dir for powepc64 and powepc64le can differ

E.g., RHEL >= 7.1 uses ppc64le for reasons listed in
https://bugs.openjdk.java.net/browse/JDK-8073139 .

Change-Id: I982e65cdf99999e8a5ed23cf444ccb2aee764c4c

configure.ac

@@ -6997,9 +6997,12 @@ then
         powerpc)
             my_java_arch=ppc
             ;;
-        powerpc64*)
+        powerpc64)
             my_java_arch=ppc64
             ;;
+        powerpc64le)
+            AS_IF([test -d "$JAVA_HOME/jre/lib/ppc64le"], [my_java_arch=ppc64le], [my_java_arch=ppc64])
+            ;;
         x86_64)
             my_java_arch=amd64
             ;;