[ivette/ci] manual tests

See merge request frama-c/frama-c!4613

match minimal requirements of dolmen.0.9 which is the minimal version
for alt-ergo(-lib).2.5.3

Feature/andre/libc improvements

See merge request frama-c/frama-c!4513

[analysis-scripts] improve and distribute estimate-difficulty executable

See merge request frama-c/frama-c!4569

E-ACSL tests are not allowed to fail

See merge request frama-c/frama-c!4610

If needed, this will be done later via machdeps and not preprocessor macros

This reverts commit 1e6f9135.

It also changes pthread_t to match the usual definition on a glibc + Linux.

This reverts commit 467f60b7.

Allow estimate-difficulty to be exported (in Linux/macOS/Windows) as
independent executable, so that it can be used without having to install
Frama-C.

Fix/ivette build

See merge request frama-c/frama-c!4611