GNU Coding Standards recommend that packages install their subsidiary executables in a subdirectory of $(libexecdir), suggesting $(libexecdir)/ $(PACKAGE)[1]. CVS m4 wants to use this idiom for installing its libtool modules, rather than $(pkglibdir) which is for object code used in linking rather than shared libraries for dlopen'ing. It would be nice if automake provided $(pkglibexecdir) alongside $(pkglibdir) and friends.
[1] http://www.gnu.org/prep/standards/standards.html#Directory-Variables -- Eric Blake
