Relation between libtool and pkg-config

[Richard Lemieux]

Hi,

This is a question about how libtool finds the libraries in a script.
The question arosed in the situation where I was compiling
'gphoto2' for an installation is a separate directory
'/rlxb4/opt/gphoto2' while there was already an older version of 'gphoto2'
installed in '/usr/local'.

I got the feeling that 'libtool' was using information from
'/usr/local/lib/pkgconfig/pghoto2.pc'  rather than from the
newly intalled '/rlxb4/opt/gphoto2/lib/pkgconfig/pghoto2.pc'
although 'PKG_CONFIG_PATH' was set up as follows

  export PKG_CONFIG_PATH=/rlxb4/opt/gphoto2/lib/pkgconfig:$PKG_CONFIG_PATH

Now I can't see anywhere in the documentation of 'libtool' what
data 'libtool' uses to find libraries: no environment variable and
no special file like the '.pc' files in 'pkg-config'.

Can anyone point me to a document explaining the general architecture of
'libtool', where it stores information, and where it takes information from,
and how it interacts with 'pkg-config'?

I have already looked in the 'info' files, and on Google.

Thank you