maint: pass directory declarations in configure.ac into Makefile.

maint: pass directory declarations in configure.ac into Makefile.

* configure.ac (AC_CONFIG_AUX_DIR, LT_CONFIG_LTDL_DIR)
(AC_CONFIG_MACRO_DIR): Append code to these functions to
capture and propagate their directory arguments to Makefile.
* Makefile.am (aux_dir, ltdl_dir, macro_dir): Remove declarations.
* bootstrap (my_sed_trace): Also capture LT_CONFIG_LTDL_DIR into
`$ltdl_dir'.
<Makefile>: Output the extracted values of `aux_dir', `ltdl_dir'
and `macro_dir' at the top of the quick'n'dirty bootstrap
Makefile.