This should either always or never be present in release builds - since it breaks binary compatibility. We may enable it always in APR 1.0 yet leave it undefined in most cases.
Global apr_dso_load (apr_dso_handle_t **res_handle, const char *path, apr_pool_t *ctx)
We aught to provide an alternative to RTLD_GLOBAL, which is the only supported method of loading DSOs today.
Global apr_proc_other_child_register (apr_proc_t *proc, void(*maintenance)(int reason, void *, int status), void *data, apr_file_t *write_fd, apr_pool_t *p)
write_fd duplicates the proc->out stream, it's really redundant and should be replaced in the APR 1.0 API with a bitflag of which proc->in/out/err handles should be health checked.