Only define the following before android-L (where new headers define
them already)
typedef khronos_int64_t GLint64;
typedef khronos_uint64_t GLuint64;
typedef struct __GLsync *GLsync;
Also define L to 9999 for crtbrand.c which needs it to be an integer
Change-Id: I9ed957d70b85cd1cdfeacf11f77203b39c93023d
"atexit" isn't defined in libc.a for x86/mips (unlike their arm's counterpart).
Include atexit.S otherwise app using atexit() may fail to link statically.
Also, add crtbegin.c to brand crtbegin_static/dynamic.c with .note.ABI-tag
section of given API level. See $NDK/gen-platforms.sh
Change-Id: I2fdbb92119e3ca2da2c1ced6d77e63136ec35c34