[libpng17] Fixed ALIGNED_MEMORY support and

Allow run-time ARM NEON checking to be disabled. A new configure option:
--enable-arm-neon=always will stop the run-time checks. New checks
within arm/arm_init.c will cause the code not to be compiled unless
__ARM_NEON__ is set. This should make it fail safe (if someone asks
for it on then the build will fail if it can't be done.)
6 files changed