diff --git a/libs/utils/Android.mk b/libs/utils/Android.mk
index 7d4524a..2bb42ab 100644
--- a/libs/utils/Android.mk
+++ b/libs/utils/Android.mk
@@ -26,6 +26,7 @@
 	Debug.cpp \
 	FileMap.cpp \
 	Flattenable.cpp \
+	ObbFile.cpp \
 	Pool.cpp \
 	RefBase.cpp \
 	ResourceTypes.cpp \
@@ -65,6 +66,11 @@
 endif
 endif
 
+ifeq ($(HOST_OS),darwin)
+# MacOS doesn't have lseek64. However, off_t is 64-bit anyway.
+LOCAL_CFLAGS += -DOFF_T_IS_64_BIT
+endif
+
 include $(BUILD_HOST_STATIC_LIBRARY)