https://bugs.gentoo.org/665364

--- a/sci-mathematics/maxima/maxima-5.43.0.ebuild
+++ b/sci-mathematics/maxima/maxima-5.43.0.ebuild
@@ -128,9 +128,19 @@ src_configure() {
 		if [ ${CONF} = . ]; then
 			CONF=${LISPS[${n}]}
 		fi
+		if [[ ${CONF} == ccl ]]; then
+			# 64-bit version of clozurecl is enabled
+			# by --enable-ccl64, not by --enable-ccl.
+			# bug #665364
+			use amd64 && CONF=ccl64
+		fi
 		CONFS="${CONFS} --enable-${CONF}"
 	done
 
+	# Gentoo calls 'ccl' both 32-bit and 64-bit version of clozurecl.
+	# bug #665364
+	CONFS="${CONFS} --with-ccl64=ccl"
+
 	# enable existing translated doc
 	if use nls; then
 		for lang in ${LANGS}; do