5.2.3 (2016-12-30)

• xz:

  - Always close a file before trying to delete it to avoid
    problems on some operating system and file system combinations.
  
  - Fixed copying of file timestamps on Windows.
  
  - Added experimental (disabled by default) sandbox support using
    Capsicum (FreeBSD >= 10). See --enable-sandbox in INSTALL.
  

• C99/C11 conformance fixes to liblzma. The issues affected at least some builds using link-time optimizations.

• Fixed bugs in the rarely-used function lzma_index_dup().

• Use of external SHA-256 code is now disabled by default. It can still be enabled by passing --enable-external-sha256 to configure. The reasons to disable it by default (see INSTALL for more details):

  - Some OS-specific SHA-256 implementations conflict with
    OpenSSL and cause problems in programs that link against both
    liblzma and libcrypto. At least FreeBSD 10 and MINIX 3.3.0
    are affected.
  
  - The internal SHA-256 is faster than the SHA-256 code in
    some operating systems.
  

• Changed CPU core count detection to use sched_getaffinity() on GNU/Linux and GNU/kFreeBSD.

• Fixes to the build-system and xz to make xz buildable even when encoders, decoders, or threading have been disabled from libilzma using configure options. These fixes added two new #defines to config.h: HAVE_ENCODERS and HAVE_DECODERS.