find_apu.m4 needs to be smarter about installed locations.

Hey All,

I recently tried to configure and build subversion with apr and apr-util not
included in my subversion tree.

I have a directory structure like this:
projects/svn
projects/apr
projects/apr-util

I buildconf; ./configure --enable-maintainer-mode; make; su -c 'make install'
in both projects/apr and projects/apr-util, resulting in installed versions of
both in /usr/local.

Then I went into projects/svn and did ./autogen.sh; ./configure \
--enable-maintainer-mode --disable-shared.

Subversion's configure failed to find apr-util. Here's my diagnoses of why.
It looks in a bunch of standard places for apr-util, including /usr/local, but
fails to link. Why? A bunch of necessary stuff is missing from the link
line. First of all, there is no mention of -lapr. Second, there are none of
the LDFLAGSS and LIBS needed by apr-util itself.

Fine I thought, I'll change it to find apu-config first and then add them in.
That didn't work because 1) apu-config doesn't mention needing apr, and 2)
apu-config --libs gives /usr/local/lib/libexpat.la which ld says is an invalid
file type.

Anyone with more autoconf experience want to step up to this one. (Note that
it works find if I pass a --with-apr-util=/usr/local to subversion's configure
script).

-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kevin Pilch-Bisson                    http://www.pilch-bisson.net
     "Historically speaking, the presences of wheels in Unix
     has never precluded their reinvention." - Larry Wall
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~