对C++进行优化了的android-ndk-r6-crystax-2

https://www.crystax.net/en/android/ndk/6?id=6

Here is customized distribution of Android NDK r6 which I have rebuilt from official sources. Starting from NDK r5, Google added support of C++ exceptions, RTTI and STL to the official NDK. That's good but not enough for many peoples including me. Starting from r5-crystax-1, main goal of this project will be improvements of official NDK (after all, this is the best way to integrate such improvements into mainline - that's how it was with full C++ support in Google's NDK).

One of such big improvements is C++ standard conformant support of wide chars (wide strings, streams etc). Finally, after months of development, it's fully completed. You shouldn't care about wide chars/strings/streams anymore when porting existing code to Android - just compile it using my NDK and go further. Download and enjoy!

有些ndk-build编译的时候，特别是编译c++文件的时候，如果链接的时候找不到某些符号，则可以将如下语句加入Android.mk：

LOCAL_ALLOW_UNDEFINED_SYMBOLS := true

根据ndk的doc，当ndk编译的时候会进行一个调试检查，见参考：

http://stackoverflow.com/questions/7209971/ndk-build-undefined-reference-to-errors-when-statically-linking-to-libxml-a

As explained in the ndk doc, it is because the ndk performs a debug checking even for avoiding runtime linking error and for some motivations it doesn't find the correct references in a pre-built library. Hope it coulds help.

另外，Application.mk也很重要，它里面应该这样：

APP_ABI := armeabi-v7a
APP_STL := gnustl_static
APP_CPPFLAGS += -frtti
APP_CPPFLAGS += -DANDROID