[CN-Exec] EOF error when NULL macro is used

[dc-mak]

#ifndef NULL           
#define NULL ((void*)0)
#endif                 
                       
int main()             
{                      
    int *p = NULL;     
}                      

15:34 ➜  VST git:(VST) ✗ /home/dhruv/.opam/4.14.1/lib/cn/runtime/libexec/cn-runtime-single-file.sh -o tmp.c
cn: internal error, uncaught exception:
    End_of_file
    Raised at Stdlib.unsafe_really_input in file "stdlib.ml", line 429, characters 9-26
    Called from Stdlib.really_input_string in file "stdlib.ml", line 440, characters 2-25
    Called from Cn__Source_injection.move_to.aux in file "backend/cn/lib/source_injection.ml", line 122, characters 10-49
    Called from Cn__Source_injection.inject in file "backend/cn/lib/source_injection.ml", line 174, characters 14-48
    Called from Stdlib__List.fold_left in file "list.ml", line 121, characters 24-34
    Called from Cn__Source_injection.inject_all in file "backend/cn/lib/source_injection.ml", line 260, characters 11-72
    Called from Cn__Source_injection.output_injections.(fun) in file "backend/cn/lib/source_injection.ml", line 419, characters 13-49
    Called from Cerb_colour.without_colour in file "util/cerb_colour.ml", line 40, characters 10-13
    Called from Cn__Executable_spec.main.(fun) in file "backend/cn/lib/executable_spec.ml", line 393, characters 7-229
    Called from Dune__exe__Main.generate_executable_specs.(fun) in file "backend/cn/bin/main.ml", line 408, characters 10-272
    Called from Cerb_colour.without_colour in file "util/cerb_colour.ml", line 40, characters 10-13
    Called from Dune__exe__Main.with_well_formedness_check in file "backend/cn/bin/main.ml", line 169, characters 6-443
    Re-raised at Dune__exe__Main.with_well_formedness_check in file "backend/cn/bin/main.ml", line 188, characters 4-69
    Called from Cmdliner_term.app.(fun) in file "cmdliner_term.ml", line 24, characters 19-24
    Called from Cmdliner_eval.run_parser in file "cmdliner_eval.ml", line 35, characters 37-44
Failed to generate C files from CN-annotatated source.

[yav]

This happens with other macros as well. Seems to be related to the length of the definition, I have an example where:

#define KEY int     // Works fine
#define VALUE long  // Works 

However, defining KEY like this causes the error above:

#define KEY unsigned int