how to link with libtool?

[Matěj Týč]

Hello,
I have a library that has its .la file in the right place.
The question is: What should I do in the autotools setup so that libtool
takes over the compilation, discovers the .la file and passes additional
options to the linker so that the linking doesn't fail? Having
AC_PROG_LIBTOOL in the configure.ac is not enough...
What about having a AC_CHECK_LTLIB macro? 
This would be good to check for libtool libs first and for pkg-config
configuration only if someone has taken the .la files away (some distros
do that)
What do you think of this?
Matej