Mac runtime fixes.

This is enough to let us run test-art-host on the Mac. The tests
that don't start a runtime (and thus don't try to dlopen(3)
libjavacore.dylib) succeed. The others fail, but I'm not sure how
the Linux tests find libjavacore.so, so I'm not sure how to fix
things for Mac OS.

Change-Id: Idf489fc09f0a8f64fbb60dfcdbca9c3df2d4fdcb
diff --git a/Android.mk b/Android.mk
index 96579c7..025f4d7 100644
--- a/Android.mk
+++ b/Android.mk
@@ -56,8 +56,14 @@
   $(foreach file,$(sort $(ART_HOST_TEST_EXECUTABLES)),$(1) $(file) &&) true
 endef
 
-ART_HOST_DEPENDENCIES   := $(ART_HOST_EXECUTABLES)   $(HOST_OUT_JAVA_LIBRARIES)/core-hostdex.jar $(HOST_OUT_SHARED_LIBRARIES)/libjavacore.so
-ART_TARGET_DEPENDENCIES := $(ART_TARGET_EXECUTABLES) $(TARGET_OUT_JAVA_LIBRARIES)/core.jar     $(TARGET_OUT_SHARED_LIBRARIES)/libjavacore.so
+ART_HOST_DEPENDENCIES := $(ART_HOST_EXECUTABLES) $(HOST_OUT_JAVA_LIBRARIES)/core-hostdex.jar
+ifeq ($(HOST_OS),linux)
+  ART_HOST_DEPENDENCIES += $(HOST_OUT_SHARED_LIBRARIES)/libjavacore.so
+else
+  ART_HOST_DEPENDENCIES += $(HOST_OUT_SHARED_LIBRARIES)/libjavacore.dylib
+endif
+
+ART_TARGET_DEPENDENCIES := $(ART_TARGET_EXECUTABLES) $(TARGET_OUT_JAVA_LIBRARIES)/core.jar $(TARGET_OUT_SHARED_LIBRARIES)/libjavacore.so
 
 ART_HOST_TEST_DEPENDENCIES   := $(ART_HOST_DEPENDENCIES)   $(ART_TEST_OAT_FILES)
 ART_TARGET_TEST_DEPENDENCIES := $(ART_TARGET_DEPENDENCIES) $(ART_TEST_OAT_FILES)