Discussion related to cado-nfs

[Andreas Enge <andreas.enge@inria.fr>]

Exporting $CC and $CXX works, assuming that one first deletes the build
directory where test results are cached. Being used to the autotools,
this is a bit surprising, and I needed the help of a cmake-savvy colleague
to figure this out. How about creating a separate script ./configure
that deletes the build directory and makes the cmake call to configure
the project, and let make handle only the build process?

Maybe the behaviour I reported is not a bug after all. I had the debian
cc, gcc and g++ in /usr/bin, and the guix gcc and g++ (no cc) in $PATH.
The configure step then used the cc in /usr/bin. So apparently cc is
checked before gcc, which is different from the autotools, but looks
like acceptable behaviour after all.

Concerning gmp, it is also in a separate directory, which is referenced
by $CPATH and $LIBRARY_PATH. I can pass it via $GMP, but it would be nice
if the check for gmp honoured these environment variables. (Well, all
these problems for the user would disappear by using the autotools...)

Currently, configuration fails with
CMake Error at config/python.cmake:9 (message):
  Python interpreter not found
Call Stack (most recent call first):
  CMakeLists.txt:142 (include)

This is at least a misleading error message: I have python-2.7 as
/usr/bin/python. Looking at config/python.cmake, it appears I need
python-3.

Andreas