Update to 1.4.71. From the changelog:

* [mod_h2] HTTP/2 separate module; no longer builtin
* [mod_magnet] fix static build using autoconf (fixes #3203)
* [core] fix new use of posix_spawn with some glibc (fixes #3201)
* [core] check getaddrinfo EAI_ADDRFAMILY w/ glibc
* [core] quiet lemon.c clang C2x warnings
* [core] compile w/o posix_spawn() on iOS
* [core] fix crash due to missing initialization (fixes #3207)
* [core] request_init() separate static func
* [multiple] remove some unused/redundant includes
* [core] server.modules s/mod_compress/mod_deflate/
* [core] preproc consistency #pragma GCC diagnostic
* [core] update ls-hpack
* [core] use empty value in srvconf.config_touched
* [core] provide mimetype.assign default if unset
* [mod_vhostdb_mysql] MySQL missing mysql_get_socket (fixes #3208)
* [core] clarify comment

(schmonz)