Thanks for the reply.
There is three way of executing Ocaml code:
1- by ocaml interpretor (not our problem here)
2- by compile to bytecode and then execute the obtained code: the bytecode is, IMHO, mainly here for debugging and historical purposes. This bytecode is very slow to execute but this is the way CG decided to compile Ocaml code (cf this thread https://www.codingame.com/forum/t/native-ocaml-compiler/937) but we can still compile to native code until yesterday
3- A very efficient native compiler which produces very fast code since the produced code can be optimized.
even if I do not understand why it seems that the line
erases the native compiler.
If you just remove this line from your script things should become normal again.
Maybe you should consider to change the line "./configure" to "./configure --prefix /usr/bin" in order to install the compilers and library into users path but it depends on your local policy.