Link libsigchain.a instead of sigchain.o

  Relative paths may sometimes lead to failed builds
  if sources are built in particular order.

  Also it is possible to export symbols from static lib
  with LOCAL_WHOLE_STATIC_LIBRARIES variable.

Change-Id: I6d62594c2e84020d67254747c1fd465e1144920e
diff --git a/dalvikvm/Android.mk b/dalvikvm/Android.mk
index 0bab429..0ef20d6 100644
--- a/dalvikvm/Android.mk
+++ b/dalvikvm/Android.mk
@@ -24,10 +24,11 @@
 LOCAL_MODULE := dalvikvm
 LOCAL_MODULE_TAGS := optional
 LOCAL_CPP_EXTENSION := cc
-LOCAL_SRC_FILES := dalvikvm.cc ../sigchainlib/sigchain.cc
+LOCAL_SRC_FILES := dalvikvm.cc
 LOCAL_CFLAGS := $(dalvikvm_cflags)
 LOCAL_C_INCLUDES := art/runtime
 LOCAL_SHARED_LIBRARIES := libdl liblog libnativehelper
+LOCAL_WHOLE_STATIC_LIBRARIES := libsigchain
 LOCAL_LDFLAGS := -Wl,--version-script,art/sigchainlib/version-script.txt -Wl,--export-dynamic
 LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
 LOCAL_ADDITIONAL_DEPENDENCIES += art/build/Android.common.mk
@@ -51,10 +52,11 @@
 LOCAL_MODULE_TAGS := optional
 LOCAL_CLANG := true
 LOCAL_CPP_EXTENSION := cc
-LOCAL_SRC_FILES := dalvikvm.cc ../sigchainlib/sigchain.cc
+LOCAL_SRC_FILES := dalvikvm.cc
 LOCAL_CFLAGS := $(dalvikvm_cflags)
 LOCAL_C_INCLUDES := art/runtime
 LOCAL_SHARED_LIBRARIES := libnativehelper
+LOCAL_WHOLE_STATIC_LIBRARIES := libsigchain
 LOCAL_LDFLAGS := -ldl -lpthread
 # Mac OS linker doesn't understand --export-dynamic.
 ifneq ($(HOST_OS),darwin)