Missing CXSC library (optionally used by Float package)

[olexandr-konovalov]

In order to build Float, one should meet the prerequisites first:

Configure: error: You need to first install the external libraries mpfr mpfi mpc cxsc fplll, and then rerun './configure'

[olexandr-konovalov]

I've added libmpfr-dev, libmpfi-dev, libmpc-dev, libfplll-dev to the docker image in commit a6fbad8. The only missing dependency is on cxsc, because it does not seem to have a fully automated installation procedure, but has to be installed interactively (it asks to agree with the license, etc.) This is why I used ./configure --without-cxsc to configure Float.

@laurentbartholdi, is this a serious limitation, and do you know a better way to install cxsc by any chance?

[olexandr-konovalov]

@sebasguts & @laurentbartholdi: since we now build `gap-docker-base' manually, perhaps we may consider adding CXSC there as well?

[olexandr-konovalov]

https://github.com/gap-system/gap-docker-base/blob/master/Dockerfile now install CSXC as well.