Fix autoconf warnings #467

Job	Run time
Empty APLOGNO() test	37s
Default	3m 49s
All-static modules	4m 4s
Prefork MPM, all-modules (except cgid)	4m 34s
Worker MPM, all-modules	4m 41s
Shared MPMs, all-modules	4m 43s
Event MPM, all-modules, mod_cgid only	5m 21s
Event MPM, all-modules, no CMSG_DATA	4m 22s
Default, all-modules + install	4m 44s
Default, all-modules, random test order	4m 23s
GCC 10 maintainer-mode w/-Werror, install + VPATH	4m 39s
All-modules, APR 1.7.4, APR-util 1.6.3	5m 20s
APR 1.8.x, APR-util 1.7.x	8m 7s
Pool-debug	6m 47s
Shared MPMs (event), pool-debug, SSL/TLS variants	12m 19s
Shared MPMs (worker), pool-debug, SSL/TLS variants	10m 41s
Shared MPMs (prefork), pool-debug, SSL/TLS variants	10m 27s
litmus WebDAV tests	2m 15s
Regenerate ap_expr	5m 14s
APR 1.7.4, APR-util 1.6.3, LDAP	4m 47s
APR trunk thread debugging	4m 25s
UBSan	5m 10s
ASan	7m 28s
ASan, pool-debug	7m 47s
HTTP/2 test suite	12m 47s
MOD_TLS test suite	7m 45s
	2h 37m 16s

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