* tools/dvecompile.cpp: Here.

* .gitlab-ci.yml: Here.

* lpsolve/lp_presolve.c: Here.

*  .gitlab-ci.yml: here.

* hoard/heaplayers/threadheap.h, hoard/userealtls.cpp,
tools/probabilistic.cpp, wibble/empty.h, wibble/mixin.h,
wibble/range.h, wibble/singleton.h: here.

* build.sh: Common build script.
* .gitlab-ci.yml: Rules for GitLab CI.

Remove all occurences of snprintf and replace by wibble::str::fmtf.

Merging dependent expressions can never be done correctly at runtime.
E.g. transitive depedencies can not easily be found.
The issue is now solved with the maybe check in previous commits.

We now use a vector instead of a set.

- add must-write
- add copy