fix build in Android 4.4 (tested with Omni)

Change-Id: I781928483585052741fe1396bd9b136e61ca6538
diff --git a/libpixelflinger/Android.mk b/libpixelflinger/Android.mk
index d464c77..693a612 100644
--- a/libpixelflinger/Android.mk
+++ b/libpixelflinger/Android.mk
@@ -91,6 +91,9 @@
 LOCAL_SRC_FILES_arm64 := $(PIXELFLINGER_SRC_FILES_arm64)
 LOCAL_SRC_FILES_x86 := $(PIXELFLINGER_SRC_FILES_x86)
 LOCAL_SRC_FILES_mips := $(PIXELFLINGER_SRC_FILES_mips)
+ifneq ($(shell test $(PLATFORM_SDK_VERSION) -gt 22; echo $$?),0)
+    LOCAL_SRC_FILES += $(LOCAL_SRC_FILES_$(TARGET_ARCH))
+endif
 LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
 LOCAL_C_INCLUDES += $(LOCAL_EXPORT_C_INCLUDE_DIRS)
 LOCAL_CFLAGS := $(PIXELFLINGER_CFLAGS)