We actually test this platform (ubuntu xenial), and gfan builds correctly.
See https://github.com/sagemath/sage/runs/3392764418?check_suite_focus=true
This failure must be caused by something specific to your system - such as
some stuff installed into /usr/local or something like that.
On
--
sage -t --long --warn-long 356.4 --random-seed=0
src/sage/calculus/riemann.pyx # Killed due to segmentation fault
--
Total time for all tests: 19434.6
Hi!
I'm afraid it's a long time since I last tried to build SageMath. When I
now checked out the latest develop branch, gfran failed to build.
>From the log:
[gfan-0.6.2.p1] IntegerVectorList setTemp;for(auto
c=observedExponents.begin();c!=observedExponents.end();c++)setTemp.push_back(*c);