libpng-1.5.17 is available from
and from

Changes since the last public release (1.5.16):

  Removed a redundant test from png_set_IHDR().
  Added set(CMAKE_CONFIGURATION_TYPES ...) to CMakeLists.txt (Andrew Hundt)
  Deleted set(CMAKE_BUILD_TYPE) block from CMakeLists.txt
  Make ARM NEON support work at compile time (not just configure time).
    This moves the test on __ARM_NEON__ into pngconf.h to avoid issues when
    using a compiler that compiles for multiple architectures at one time.
    pnglibconf.h, allowing more of the decisions to be made internally
    (pngpriv.h) during the compile.  Without this, symbol prefixing is broken
    under certain circumstances on ARM platforms.  Now only the API parts of
    the optimizations ('check' vs 'api') are exposed in the public header files
    except that the new setting PNG_ARM_NEON_OPT documents how libpng makes the
    decision about whether or not to use the optimizations.
  Protect symbol prefixing against CC/CPPFLAGS/CFLAGS useage.
    Previous iOS/Xcode fixes for the ARM NEON optimizations moved the test
    on __ARM_NEON__ from configure time to compile time.  This breaks symbol
    prefixing because the definition of the special png_init_filter_functions
    call was hidden at configure time if the relevant compiler arguments are
    passed in CFLAGS as opposed to CC.  This change attempts to avoid all
    the confusion that would result by declaring the init function even when
    it is not used, so that it will always get prefixed.
  Revised libpng.3 so that "doclifter" can process it.
  Revised example.c to illustrate use of PNG_DEFAULT_sRGB and PNG_GAMMA_MAC_18
    as parameters for png_set_gamma().  These have been available since

Armored detached gpg signatures are in the Gnupg subdirectory..