diff --git a/src/conf.h b/src/conf.h
index f2424ec1..7fc18dd4 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -199,18 +199,29 @@ typedef void (__acc_cdecl *upx_progress_func_t)
 
 struct upx_callback_t
 {
+#if 0
     upx_alloc_func_t nalloc;
     upx_free_func_t nfree;
+#endif
     upx_progress_func_t nprogress;
     void * user1;
+#if 0
     unsigned user2;
     unsigned user3;
+#endif
 };
 
 
 struct lzma_compress_config_t
 {
     unsigned max_num_probs;
+#if 0
+    unsigned pos_bits;              // pb
+    unsigned lit_pos_bits;          // lp
+    unsigned lit_context_bits;      // lc
+    unsigned dict_size;
+    unsigned mf_passes;
+#endif
     void reset() { memset(this, 0, sizeof(*this)); }
 };
 
diff --git a/src/options.h b/src/options.h
index 0511fde0..5b7d5c00 100644
--- a/src/options.h
+++ b/src/options.h
@@ -86,6 +86,13 @@ struct options_t {
     // compression runtime parameters - see struct ucl_compress_config_t
     struct crp_lzma_t {
         int dummy;
+#if 0
+        unsigned pos_bits;              // pb
+        unsigned lit_pos_bits;          // lp
+        unsigned lit_context_bits;      // lc
+        unsigned dict_size;
+        unsigned mf_passes;
+#endif
         void reset() { memset(this, 0, sizeof(*this)); }
     };
     struct crp_ucl_t {