I'm running make check right now...I forgot to earlier as I was too excited. And as far apr, it does include the headers in /usr/include.
iPhone:~ root dpkg -L apr
/.
/usr
/usr/bin
/usr/bin/apr-1-config
/usr/include
/usr/include/apr-1
/usr/include/apr-1/apr_fnmatch.h
/usr/include/apr-1/apr_tables.h
/usr/include/apr-1/apr_atomic.h
/usr/include/apr-1/apr_global_mutex.h
/usr/include/apr-1/apr_general.h
/usr/include/apr-1/apr_ring.h
/usr/include/apr-1/apr_poll.h
/usr/include/apr-1/apr_thread_rwlock.h
/usr/include/apr-1/apr_thread_mutex.h
/usr/include/apr-1/apr_strings.h
/usr/include/apr-1/apr_proc_mutex.h
/usr/include/apr-1/apr_mmap.h
/usr/include/apr-1/apr_user.h
/usr/include/apr-1/apr_network_io.h
/usr/include/apr-1/apr_shm.h
/usr/include/apr-1/apr_pools.h
/usr/include/apr-1/apr_getopt.h
/usr/include/apr-1/apr_want.h
/usr/include/apr-1/apr_version.h
/usr/include/apr-1/apr_dso.h
/usr/include/apr-1/apr_hash.h
/usr/include/apr-1/apr_portable.h
/usr/include/apr-1/apr_random.h
/usr/include/apr-1/apr_file_info.h
/usr/include/apr-1/apr_allocator.h
/usr/include/apr-1/apr_file_io.h
/usr/include/apr-1/apr.h
/usr/include/apr-1/apr_inherit.h
/usr/include/apr-1/apr_time.h
/usr/include/apr-1/apr_errno.h
/usr/include/apr-1/apr_env.h
/usr/include/apr-1/apr_thread_cond.h
/usr/include/apr-1/apr_lib.h
/usr/include/apr-1/apr_support.h
/usr/include/apr-1/apr_thread_proc.h
/usr/include/apr-1/apr_signal.h
aka
--with-apr=/usr
No, I meant the 'build-1' directory that should be located in /usr. That contains some useful things like a modified libtool and the macros defined when building APR. Those, for example, are used in building apr-util and dependencies.
Edit: specifically, it contains:
apr_rules.mk libtool make_exports.awk make_var_export.awk mkdir.sh