Restore strerror as %m is unsupported by the BSDs

The BSDs just print m instead of the actual error message. Benefit
is not worth the cost.

src/debugfile.c

@@ -119,7 +119,7 @@ int debugfile_init (hashcat_ctx_t *hashcat_ctx)
     {
       fclose (fp);
 
-      event_log_error (hashcat_ctx, "%s: %m", debugfile_ctx->filename);
+      event_log_error (hashcat_ctx, "%s: %s", debugfile_ctx->filename, strerror (errno));
 
       return -1;
     }