configure script asumes protobuf installed on standard locations

[GoogleCodeExporter]

As of r33, the configure script asumes protobuf is installed on standard 
locations (headers under /usr/include, libraries under /usr/bin).

If ``pkg-config`` is installed, one can always do the following:

  $ env CPPFLAGS="$(pkg-config --cflags protobuf)" \
        LIBS="$(pkg-config --libs protobuf)" \
            ./configure [..]

The attached diff eliminates the need to do that, and simplifies a bit 
``configure.ac`` -- it also makes building ``szl`` depend on ``pkg-config``, 
though.

Original issue reported on code.google.com by [email protected] on 5 Nov 2010 at 6:24

Attachments:

• protobuf-location-with-pkg-config.diff