backends need some OO loving

[Matt Hoosier]

> BTW: If you're autotools-literate please take a look at
> backend/common/Makefile.am -- it works but I'd like to see if automake
> can make this more automatic...
> http://gitweb.freedesktop.org/?p=geoclue.git;a=blob;f=backend/common/Makefile.am

Do you ever want some backend to link one of those, but not the other?
I guess this is why you separated the two sets of CFLAGS and LDFLAGS
out.

I'd recommend using a convenience library, to avoiding "guessing" the
name of the object files. It'd be something like:

  noinst_LIBRARIES = libgeoclue_web_service.a libgeoclue_position_error.a

  libgeoclue_web_service_a_CFLAGS += ...
  libgeoclue_position_error_a_CFLAGS ++ ...

Then of course you have to change the sites that currently do something like:

  my_backend_LIBADD = .../common/libgeoclue_web_service.a

--Matt