Force alignment on arm32

This fixes our test failures on Debian-based arm32v7, and fixes *most* of our test failures on Alpine-based arm32v{6,7}, leaving the notable `t/restart.t` which we've had issues with prior.

Author: tianon

1/alpine/Dockerfile

@@ -91,6 +91,10 @@ RUN set -eux; \
 	cd /usr/src/memcached; \
 	\
 	gnuArch="$(dpkg-architecture --query DEB_BUILD_GNU_TYPE)"; \
+# https://github.com/memcached/memcached/issues/1220#issuecomment-2770251664: on arm32, we need to override the upstream alignment check (which fails to detect the need for alignment on arm32 on our hardware for some reason, which then causes us to fail the tests 😭)
+	case "$gnuArch" in \
+		arm-*) export ac_cv_c_alignment=need ;; \
+	esac; \
 	./configure \
 		--build="$gnuArch" \
 		--enable-extstore \