add int64_t and uint64_t definitions.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1956 bbd45198-f89e-11dd-88c7-29a3b14d5316

components/libc/minilibc/stdint.h

@@ -9,6 +9,8 @@ typedef	rt_int16_t		int16_t;
 typedef	rt_uint16_t		uint16_t;
 typedef	rt_int32_t		int32_t;
 typedef	rt_uint32_t		uint32_t;
+typedef long long		int64_t;
+typedef unsigned long long uint64_t;
 
 /*
  * 7.18.2 Limits of specified-width integer types.