Minor code fix to get rid of Coverity warning (I hope).

src/pcre2_serialize.c

@@ -7,7 +7,7 @@ and semantics are as close as possible to those of the Perl 5 language.
 
                        Written by Philip Hazel
      Original API code Copyright (c) 1997-2012 University of Cambridge
-          New API code Copyright (c) 2016-2017 University of Cambridge
+          New API code Copyright (c) 2016-2018 University of Cambridge
 
 -----------------------------------------------------------------------------
 Redistribution and use in source and binary forms, with or without
@@ -133,14 +133,18 @@ for (i = 0; i < number_of_codes; i++)
   deserialization. In order to ensure that the serialized data stream is always 
   the same for the same pattern, set them to zero here. We can't assume the 
   copy of the pattern is correctly aligned for accessing the fields as part of 
-  a structure. */
+  a structure. Note the use of sizeof(void *) in the second of these, to
+  specify the size of a pointer. If sizeof(uint8_t *) is used (tables is a 
+  pointer to uint8_t), gcc gives a warning because the first argument is also a 
+  pointer to uint8_t. Casting the first argument to (void *) can stop this, but 
+  it didn't stop Coverity giving the same complaint. */
   
-  (void)memset((void *)(dst_bytes + offsetof(pcre2_real_code, memctl)), 0, 
+  (void)memset(dst_bytes + offsetof(pcre2_real_code, memctl), 0, 
     sizeof(pcre2_memctl));
-  (void)memset((void *)(dst_bytes + offsetof(pcre2_real_code, tables)), 0, 
-    sizeof(uint8_t *));
-  (void)memset((void *)(dst_bytes + offsetof(pcre2_real_code, executable_jit)),
-    0, sizeof(void *));        
+  (void)memset(dst_bytes + offsetof(pcre2_real_code, tables), 0, 
+    sizeof(void *));
+  (void)memset(dst_bytes + offsetof(pcre2_real_code, executable_jit), 0,
+    sizeof(void *));        
  
   dst_bytes += re->blocksize;
   }