Wrap atomic functions with hc_ prefix to have better platform control

include/emu_general.h

@@ -23,8 +23,8 @@ typedef struct digest
 } digest_t;
 #endif
 
-u32 atomic_dec (u32 *p);
-u32 atomic_inc (u32 *p);
+u32 hc_atomic_dec (u32 *p);
+u32 hc_atomic_inc (u32 *p);
 
 size_t get_global_id  (u32 dimindx __attribute__((unused)));
 size_t get_local_id   (u32 dimindx __attribute__((unused)));