php-fpm fails to build with ldap enabled under mac m1 (arm64)

php-fpm/Dockerfile

@@ -715,7 +715,8 @@ ARG INSTALL_LDAP=false
 
 RUN if [ ${INSTALL_LDAP} = true ]; then \
     apt-get install -yqq libldap2-dev && \
-    docker-php-ext-configure ldap --with-libdir=lib/x86_64-linux-gnu/ && \
+    ARCH=$(arch)   && \
+    docker-php-ext-configure ldap --with-libdir="lib/${ARCH}-linux-gnu/" && \
     docker-php-ext-install ldap \
 ;fi