Merge branch '2.4.x' into 2.5.x
* 2.4.x:
Release 2.4.5.
math/group-parse.c (group-parse): Parse binary-group descriptions.
math/group-parse.c: Fix copyright notice.
*.c: Check for ARM64 SIMD before using the accelerated code.
base/dispatch.c: Recognize `CPUFEAT_ARM_NEON' as requesting ARM64 SIMD.
symm/t/chacha: Missing test from RFC8439.
math/t/{mpx,mpmont}: Add some extra tests for flushing out `mul4' bugs.
math/mpx-mul4-*: Test the `...zc' variants too.
math/Makefile.am, symm/Makefile.am: Use `--no-install' on oddball tests.
progs/pixie.c: Don't crash when trying to set an empty passphrase.
configure.ac, vars.am: Use host-specific link options for test programs.