fix: remove call to awk in Makefile, replacing it by an ocaml script
because some old versions of awk are buggy
cf. https://github.com/ocaml/opam/issues/1247

modified:   Makefile
new file:   shell/modulename_of_mlfilename.ml
Merge pull request #1251 from pw374/master

fix: remove call to awk in Makefile, replacing it by an ocaml script