Hi
First of all, I am not sure if I am writing this to the correct mailing
list. If not, please tell me where should I send this.

I am trying to install gsl (https://opam.ocaml.org/packages/gsl/gsl.1.19.1/)
with opam.
I previously installed OCaml 4.02.3 with opam.

I get this message error when I do "opam install gsl":

The following actions will be performed:
  ∗  install conf-ncurses 1                   [required by ocamlfind]
  ∗  install conf-gsl     1                   [required by gsl]
  ∗  install ocamlfind    1.6.1               [required by gsl]
  ∗  install gsl          1.19.1
===== ∗  4 =====
Do you want to continue ? [Y/n] y

=-=- Gathering sources
=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[gsl] Archive in cache
[ocamlfind] Archive in cache

=-=- Processing actions
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
[ERROR] The compilation of conf-gsl failed at "pkg-config gsl".
[ERROR] The compilation of conf-ncurses failed at "pkg-config ncurses".

#=== ERROR while installing conf-gsl.1
========================================#
# opam-version 1.2.2
# os           linux
# command      pkg-config gsl
# path         /home/jmazel/.opam/4.02.3/build/conf-gsl.1
# compiler     4.02.3
# exit-code    127
# env-file
/home/jmazel/.opam/4.02.3/build/conf-gsl.1/conf-gsl-10926-5f1023.env
# stdout-file
/home/jmazel/.opam/4.02.3/build/conf-gsl.1/conf-gsl-10926-5f1023.out
# stderr-file
/home/jmazel/.opam/4.02.3/build/conf-gsl.1/conf-gsl-10926-5f1023.err


#=== ERROR while installing conf-ncurses.1
====================================#
# opam-version 1.2.2
# os           linux
# command      pkg-config ncurses
# path         /home/jmazel/.opam/4.02.3/build/conf-ncurses.1
# compiler     4.02.3
# exit-code    127
# env-file
/home/jmazel/.opam/4.02.3/build/conf-ncurses.1/conf-ncurses-10926-58c514.env
# stdout-file
/home/jmazel/.opam/4.02.3/build/conf-ncurses.1/conf-ncurses-10926-58c514.out
# stderr-file
/home/jmazel/.opam/4.02.3/build/conf-ncurses.1/conf-ncurses-10926-58c514.err
### stdout ###




=-=- Error report
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
The following actions were aborted
  ∗  install gsl       1.19.1
  ∗  install ocamlfind 1.6.1
The following actions failed
  ∗  install conf-gsl     1
  ∗  install conf-ncurses 1
No changes have been performed

=-=- conf-gsl.1 troobleshooting
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
=> This package relies on external (system) dependencies that may be
missing. `opam depext conf-gsl.1' may help you find the correct
installation for
   your system.

=-=- conf-ncurses.1 troobleshooting
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
=> This package relies on external (system) dependencies that may be
missing. `opam depext conf-ncurses.1' may help you find the correct
installation
   for your system.

opam depext conf-gsl.1 yields:
# Detecting depexts using flags: x86_64 linux debian
# The following system packages are needed:
#  - libgsl0-dev
Not running as root, the following command will be run through "sudo":
    apt-get install -qq -yy libgsl0-dev
# OS packages installation successful

opam depext conf-ncurses.1 yields:
# Detecting depexts using flags: x86_64 linux debian
# The following system packages are needed:
#  - ncurses-dev
Not running as root, the following command will be run through "sudo":
    apt-get install -qq -yy ncurses-dev
# OS packages installation successful

If I rerun "opam install gsl", I get the same output as above.
And no matter how many times I run "opam depext conf-gsl.1" and "opam
depext conf-ncurses.1", no new packages are installed.

libncurses5-dev is installed. Its version is 6.0+20160213-1.
libgsl-dev is installed. Its version is 2.1+dfsg-2.

As a side note, on my system compiler (4.02.3), libocamlgsl-ocaml-dev is
installed and it has no dependency problems.

Thank you very much for your time.
Regards,
Johan