use size_t instead int to avoid compile warning

HISTORY

@@ -1,5 +1,8 @@
 
-Version 1.78  2025-08-20
+Version 1.79  2025-08-20
+  * logger.h export function log_it_ex3
+
+Version 1.78  2025-08-07
   * getIpaddrByName: normalize ip addr when input addr is IPv4 or IPv6
   * add files: spinlock.[hc]
   * shared_func.[hc]: change int2buff, buff2int etc. functions to static inline

src/shared_func.h

@@ -1632,7 +1632,7 @@ static inline int fc_ltostr(int64_t n, char *buff)
 
 static inline size_t fc_strlcpy(char *dest, const char *src, const size_t size)
 {
-    int len;
+    size_t len;
 
     len = strlen(src);
     if (len < size) {