Dear Maintainer,

I tryed to build a projet with cabal on stretch.
That think was working on jessie but now, I get an error
 message like this during the configuration.

:~/hkl/contrib/haskell$ cabal configure
Resolving dependencies...
Configuring hkl-0.1.0.0...
cabal: Missing dependencies on foreign libraries:
* Missing C libraries: hkl, gsl
This problem can usually be solved by installing the system packages that
provide these libraries (you may need the "-dev" versions). If the libraries
are already installed but in a non-standard location then you can use the
flags --extra-include-dirs= and --extra-lib-dirs= to specify where they are.

the dependency is defined via pkgconfig-depends: hkl

Indeed the C library was installed with the libhkl-dev package and it was working on jessie.

thanks for your help

Frederic