use precompiled ecj.

--- openjdk-6.orig/Makefile	2011-02-28 17:02:07.000000000 +0100
+++ openjdk-6/Makefile	2011-04-06 19:47:19.261818496 +0200
@@ -25,9 +25,7 @@
 
 BUILD_PARENT_DIRECTORY=.
 
-ifndef TOPDIR
-  TOPDIR:=.
-endif
+TOPDIR:=.
 
 ifndef JDK_TOPDIR
   JDK_TOPDIR=$(TOPDIR)/jdk
--- icedtea6-1.10.orig/Makefile.in	2011-03-02 20:48:45.161291458 +0100
+++ icedtea6-1.10/Makefile.in	2011-04-06 20:10:40.581819545 +0200
@@ -1643,10 +1643,14 @@
 
 stamps/native-ecj.stamp: 
 	mkdir -p stamps ; \
-	if test "x$(GCJ)" != "xno"; then \
-	  $(GCJ) $(IT_CFLAGS) -Wl,-Bsymbolic -findirect-dispatch -o native-ecj \
-	    --main=org.eclipse.jdt.internal.compiler.batch.Main ${ECJ_JAR} ; \
-	fi ; \
+	if test -n "${ADK_ECJ}" && test -x "${ADK_ECJ}"; then \
+		ln -s "${ADK_ECJ}" native-ecj; \
+	else \
+		if test "x$(GCJ)" != "xno"; then \
+		  $(GCJ) $(IT_CFLAGS) -Wl,-Bsymbolic -findirect-dispatch -o native-ecj \
+		    --main=org.eclipse.jdt.internal.compiler.batch.Main ${ECJ_JAR} ; \
+		fi ; \
+	fi; \
 	touch stamps/native-ecj.stamp
 
 clean-native-ecj: