Fixed configure.ac for nettle crypt library #295

Job	Run time
build (ubuntu:24.04)	8m 27s
build (ubuntu:22.04)	7m 3s
build (ubuntu:20.04)	6m 37s
build (debian:bookworm)	7m 3s
build (debian:bullseye)	6m 19s
build (rockylinux:9)	5m 58s
build (rockylinux:8)	6m 13s
build (fedora:41)	6m 37s
build (fedora:40)	6m 39s
build (alpine:3.20)	8m 42s
build (alpine:3.19)	6m 28s
build (alpine:3.18)	6m 16s
dockerimage (alpine:3.20,alpine:3.20,alpine,default)	1m 1s
dockerimage (ubuntu:24.04,ubuntu:24.04,ubuntu)	1m 44s
	1h 25m 7s

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