2.4.x: add IPv6 link-local scope ID support with APR 1.7+ #850

Job	Run time
Empty APLOGNO() test	23s
Default	3m 24s
All-static modules	3m 22s
Prefork MPM, all-modules (except cgid)	4m 15s
Worker MPM, all-modules	4m 11s
Shared MPMs, all-modules	3m 59s
Event MPM, all-modules, mod_cgid only	3m 55s
Event MPM, all-modules, no CMSG_DATA	3m 53s
Default, all-modules + install	4m 2s
Default, all-modules, random test order	4m 9s
GCC 10 maintainer-mode w/-Werror, install + VPATH	3m 23s
All-modules, APR 1.7.4, APR-util 1.6.3	4m 6s
APR 1.8.x, APR-util 1.7.x	6m 3s
Pool-debug	6m 23s
Shared MPMs (event), pool-debug, SSL/TLS variants	7m 33s
Shared MPMs (worker), pool-debug, SSL/TLS variants	7m 55s
Shared MPMs (prefork), pool-debug, SSL/TLS variants	8m 41s
litmus WebDAV tests	2m 14s
APR 1.7.4, APR-util 1.6.3, LDAP	6m 40s
APR trunk thread debugging	4m 33s
ASan	6m 12s
ASan, pool-debug	6m 48s
HTTP/2 test suite	10m 59s
MOD_TLS test suite	3m 24s
	2h 0m 27s

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