improve portability by removing rdtsc calls

https://github.com/vysheng/tg/issues/8

mtproto-client.c

@@ -90,14 +90,13 @@ struct connection_methods auth_methods = {
 };
 
 long long precise_time;
-long long precise_time_rdtsc;
+
 double get_utime (int clock_id) {
   struct timespec T;
   my_clock_gettime (clock_id, &T);
   double res = T.tv_sec + (double) T.tv_nsec * 1e-9;
   if (clock_id == CLOCK_REALTIME) {
     precise_time = (long long) (res * (1LL << 32));
-    precise_time_rdtsc = rdtsc ();
   }
   return res;
 }

mtproto-common.c

@@ -67,6 +67,9 @@ int get_random_bytes (unsigned char *buf, int n) {
       }
     }
     close (h);
+    if (r < 0) {
+      r = 0;
+    }
   }
 
   if (r < n) {
@@ -105,18 +108,15 @@ void my_clock_gettime (int clock_id UU, struct timespec *T) {
 #endif
 }
 
-
 void prng_seed (const char *password_filename, int password_length) {
   unsigned char *a = talloc0 (64 + password_length);
-  long long r = rdtsc ();
   struct timespec T;
   my_clock_gettime (CLOCK_REALTIME, &T);
   memcpy (a, &T.tv_sec, 4);
-  memcpy (a+4, &T.tv_nsec, 4);
-  memcpy (a+8, &r, 8);
+  memcpy (a + 4, &T.tv_nsec, 4);
   unsigned short p = getpid ();
-  memcpy (a + 16, &p, 2);
-  int s = get_random_bytes (a + 18, 32) + 18;
+  memcpy (a + 8, &p, 2);
+  int s = get_random_bytes (a + 10, 32) + 10;
   if (password_filename) {
     int fd = open (password_filename, O_RDONLY);
     if (fd < 0) {

mtproto-common.h

@@ -375,12 +375,6 @@ static inline void fetch_skip_str (void) {
   fetch_str (l);
 }
 
-static __inline__ unsigned long long rdtsc(void) {
-  unsigned hi, lo;
-  __asm__ __volatile__ ("rdtsc" : "=a"(lo), "=d"(hi));
-  return ( (unsigned long long)lo)|( ((unsigned long long)hi)<<32 );
-}
-
 static inline long have_prefetch_ints (void) {
   return in_end - in_ptr;
 }