message: undef some more for gcc 5.4
diff: @@ -321,7 +321,7 @@ namespace duckdb_jemalloc {
  * MADV_FREE, though typically with higher
  * system overhead.
  */
  -#define JEMALLOC_PURGE_MADVISE_FREE
  +//#define JEMALLOC_PURGE_MADVISE_FREE
  #define JEMALLOC_PURGE_MADVISE_DONTNEED
  /* #undef JEMALLOC_PURGE_MADVISE_DONTNEED_ZEROS */
  