apr-utils fails to cross build from source, because it uses mysql_config
and mysql_config does never work during cross compilation. A good
alternative is using pkg-config. I'm attaching an upstreamable patch to
update configure to use pkg-config. Since it uses the standard
PKG_CHECK_MODULES macro, it requires pkg.m4 from pkg-config. In
apr-util, doing so requires an appropriate sinclude directive. Very
likely, upstream would want a vendor copy of pkg.m4, which is not
included in my patch. Beyond this, pkg-config only kicks in when passing
yes to --with-mysql, otherwise it keeps using mysql_config for maximum
backwards compatibility. Please consider applying the patch.

Helmut