The documentation for AC_ERLANG_SUBST_INSTALL_LIB_DIR states """ its default value is @samp{$ERLANG_INSTALL_LIB_DIR/@var{librar...@var{version}}, the value of the @code{ERLANG_INSTALL_LIB_DIR} variable being set by the @code{AC_ERLANG_SUBST_INSTALL_LIB_DIR} macro. """ (This blames back to 0527671a0606 in 2006.) However, a quick inspection of the macro source reveals that the actual default is "LIBDIR/erlang/lib", and this was the case even when the documentation was written.
I'd be willing to contribute a patch to either make the docs match the implementation or the implementation match the docs, whichever you prefer. (I think the latter might be more useful.) --David