Merge branch 'maint-0.3.3' into maint-0.3.4

diff --cc configure.ac
Simple merge

diff --cc src/common/compress_zstd.c
index 316a3fb417d13d316152fb7af08164eca6c56534,b9f9f1f076995d9c39e152dbcaefebad56fa80b7..dc8b4d621d9352dfa4dde9615ea3469bef65a8d2
--- 1/src/common/compress_zstd.c
--- 2/src/common/compress_zstd.c
+++ b/src/common/compress_zstd.c
@@@ -18,18 -18,15 +18,22 @@@
  #include "compress.h"
  #include "compress_zstd.h"
  
 +#ifdef ENABLE_ZSTD_ADVANCED_APIS
 +/* This is a lie, but we make sure it doesn't get us in trouble by wrapping
 + * all invocations of zstd's static-only functions in a check to make sure
 + * that the compile-time version matches the run-time version. */
 +#define ZSTD_STATIC_LINKING_ONLY
 +#endif
 +
  #ifdef HAVE_ZSTD
+ #ifdef HAVE_CFLAG_WUNUSED_CONST_VARIABLE
  DISABLE_GCC_WARNING(unused-const-variable)
+ #endif
  #include <zstd.h>
+ #ifdef HAVE_CFLAG_WUNUSED_CONST_VARIABLE
  ENABLE_GCC_WARNING(unused-const-variable)
  #endif
+ #endif
  
  /** Total number of bytes allocated for Zstandard state. */
  static atomic_counter_t total_zstd_allocation;