Fix "Too many open files" error for aapt built with Mac OS X SDK 10.6.

With SDK 10.6 without _DARWIN_UNLIMITED_STREAMS aapt sometimes fails
right away with the error "Too many open files" when calling fopen().

Change-Id: Ifa7bd8a9530d706aa47f98be8186f1aefe943d76

Author: Ying Wang

tools/aapt/Android.mk

@@ -29,6 +29,10 @@ LOCAL_SRC_FILES := \
 
 
 LOCAL_CFLAGS += -Wno-format-y2k
+ifeq (darwin,$(HOST_OS))
+LOCAL_CFLAGS += -D_DARWIN_UNLIMITED_STREAMS
+endif
+
 
 LOCAL_C_INCLUDES += external/expat/lib
 LOCAL_C_INCLUDES += external/libpng