It is thus the responsability of the blocking simcalls to call
`SIMIX_simcall_answer(simcall)` themselves in their handler.
+Note that empty HANDLERs can be omitted. These functions usually do
+some parameter checking, or retrieve some information about the
+simcall issuer, but when there no need for such things, the handler
+can be omited. In that case, we directly call the function
+`simcall_<name>(<args>)`.
+
To simplify the simcall creation, a python script generates most of
the code and give helpers for the remaining stuff. That script reads
the simcall definitions from src/simix/simcalls.in, checks that both
