[fusion] to activate, test availability of _mm_insert_epi64

[fusion] unify detection scheme

[ipv6] fix address token validation failures

[access-log] to ease merging, use one line of source code per each attribute

[http3] support ECN

update neverbleed

Fix a build error on CMake < 3.0 systems (like RHEL 7.x)

The project requires CMake version 2.8.12 as a minimum, but actually
a build error occurs on systems with less than 3.0.

The error is as follows:
```
  CMake Error at CMakeLists.txt:24 (CMAKE_POLICY):
    Policy "CMP0042" is not known to this version of CMake.

  (snip)

  -- Configuring incomplete, errors occurred!
```

The document(*) says "This policy was introduced in CMake version 3.0",
so avoid the error by inserting the version guard.
  (*) https://cmake.org/cmake/help/v3.0/policy/CMP0042.html

Install fixes

h2 rapid reset followup

[http2] rapid reset attack