Logger: fix intel compilation

Intel does not accept the addition to a void *. Therefore I am now casting the pointers to char *

logger/logger_header.c

@@ -93,8 +93,8 @@ void header_change_offset_direction(struct header *h,
   /* Skip file format and version numbers. */
   size_t offset = LOGGER_VERSION_SIZE + 2 * sizeof(int);
 
-  logger_loader_io_write_data(h->log->log.map + offset, sizeof(unsigned int),
-                              &new_value);
+  logger_loader_io_write_data((char *)h->log->log.map + offset,
+                              sizeof(unsigned int), &new_value);
 }
 
 /**
@@ -183,9 +183,9 @@ void header_read(struct header *h, struct logger_logfile *log) {
   }
 
   /* Check the logfile header's size. */
-  if (map != log->log.map + h->offset_first_record) {
+  if (map != (char *)log->log.map + h->offset_first_record) {
     header_print(h);
-    size_t offset = map - log->log.map;
+    size_t offset = (char *)map - (char *)log->log.map;
     error("Wrong header size (in header %zi, current %zi).",
           h->offset_first_record, offset);
   }