Fix a handful of errors and warnings I've seen. Gets further running in docker, now.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@3773 ed5197a5-7fde-0310-b194-c3ffbd925b24

src/ssb.db.c

@@ -192,7 +192,10 @@ bool tf_ssb_db_blob_get(tf_ssb_t* ssb, const char* id, uint8_t** out_blob, size_
 			if (out_blob)
 			{
 				*out_blob = malloc(size + 1);
-				memcpy(*out_blob, blob, size);
+				if (size)
+				{
+					memcpy(*out_blob, blob, size);
+				}
 				(*out_blob)[size] = '\0';
 			}
 			if (out_size)