fix compiler warning

lib/hostip.c

@@ -163,9 +163,11 @@ void Curl_global_host_cache_dtor(void)
  */
 int Curl_num_addresses(const Curl_addrinfo *addr)
 {
-  int i;
-  for (i = 0; addr; addr = addr->ai_next, i++)
-    ;  /* empty loop */
+  int i = 0;
+  while(addr) {
+    addr = addr->ai_next;
+    i++;
+  }
   return i;
 }
 

lib/http.c

@@ -203,10 +203,9 @@ char *Curl_copy_header_value(const char *h)
     ++h;
 
   /* Find the first non-space letter */
-  for(start=h;
-      *start && ISSPACE(*start);
-      start++)
-    ;  /* empty loop */
+  start = h;
+  while(*start && ISSPACE(*start))
+    start++;
 
   /* data is in the host encoding so
      use '\r' and '\n' instead of 0x0d and 0x0a */
@@ -215,10 +214,12 @@ char *Curl_copy_header_value(const char *h)
     end = strchr(start, '\n');
   if(!end)
     end = strchr(start, '\0');
+  if(!end)
+    return NULL;
 
   /* skip all trailing space letters */
-  for(; ISSPACE(*end) && (end > start); end--)
-    ;  /* empty loop */
+  while((end > start) && ISSPACE(*end))
+    end--;
 
   /* get length of the type */
   len = end-start+1;

lib/transfer.c

@@ -1255,10 +1255,9 @@ static CURLcode readwrite_headers(struct SessionHandle *data,
       char *start;
 
       /* Find the first non-space letter */
-      for(start=k->p+17;
-	  *start && ISSPACE(*start);
-	  start++)
-	;  /* empty loop */
+      start = k->p + 17;
+      while(*start && ISSPACE(*start))
+        start++;
 
       /* Record the content-encoding for later use */
       if(checkprefix("identity", start))

lib/url.c

@@ -231,8 +231,10 @@ void Curl_safefree(void *ptr)
 static void close_connections(struct SessionHandle *data)
 {
   /* Loop through all open connections and kill them one by one */
-  while(-1 != ConnectionKillOne(data))
-    ; /* empty loop */
+  long i;
+  do {
+    i = ConnectionKillOne(data);
+  while(i != -1L);
 }
 
 void Curl_freeset(struct SessionHandle * data)