Link sigchain to surfaceflinger main executable

And export necessary symbols to preempt calls from libart.so

Bug: 15345057
Bug: 15426766
Change-Id: If0b7f59a59824e30aa0c33dad76c7a44932180de

services/surfaceflinger/Android.mk

@@ -106,17 +106,24 @@ include $(BUILD_SHARED_LIBRARY)
 # build surfaceflinger's executable
 include $(CLEAR_VARS)
 
-LOCAL_CFLAGS:= -DLOG_TAG=\"SurfaceFlinger\"
+LOCAL_LDFLAGS := -Wl,--version-script,art/sigchainlib/version-script.txt -Wl,--export-dynamic
+LOCAL_CFLAGS:= -DLOG_TAG=\"SurfaceFlinger\" -Iart
+LOCAL_CPPFLAGS:= -std=c++11
 
+# TODO: Trying to link libsigchain as a static library prevents
+# static linker from exporting necessary symbols. So as a workaround
+# we use sigchain.o
 LOCAL_SRC_FILES:= \
-	main_surfaceflinger.cpp 
+	main_surfaceflinger.cpp \
+	sigchain_proxy.cpp
 
 LOCAL_SHARED_LIBRARIES := \
 	libsurfaceflinger \
 	libcutils \
 	liblog \
 	libbinder \
-	libutils
+	libutils \
+	libdl
 
 LOCAL_MODULE:= surfaceflinger
 

services/surfaceflinger/sigchain_proxy.cpp

@@ -0,0 +1,17 @@
+/*
+ * Copyright (C) 2014 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "sigchainlib/sigchain.cc"