1) aclocal expects autoconf/automake macros to be hidden;
2) GTK+ hid its autoconf/automake macros;
and, if both places exist but aren't the same directory, returns a "-I"
flag to tell aclocal to look in GTK+'s directory.
Then have "autogen.sh", and Makefiles in directories with "acinclude.m4"
files, use that script and pass what flag it supplies, if any, to
aclocal.
This should, I hope, avoid problems such as those FreeBSD systems where
GTK+ was installed from a port or package (and thus stuck its macros in
"/usr/X11R6/share/aclocal") but aclocal doesn't look there.
(It doesn't solve the problem of somebody downloading and installing,
say, libtool from source - which means it probably shows up under
"/usr/local", with its macros in "/usr/local/share/aclocal" - on a
system that comes with aclocal (meaning it probably just looks in
"/usr/share/aclocal", but that may be best fixed by, whenever you
download a source tarball for something that's part of your OS,
configuring it to install in the standard system directories and
*overwriting* your OS's version.)
svn path=/trunk/; revision=2165