Including okon.h from C code results in compiler errors

[cppforliving]

Minimal example to reproduce the issue on UNIX-like OS (Ubuntu 18.04 + GCC 7.5.0 in this case)

$ echo >test.c "#include <okon/okon.h>" && cc test.c -I "<okon_root_dir>/include"
In file included from test.c:1:0:
<okon_root_dir>/include/okon/okon.h:45:1: error: unknown type name ‘okon_prepare_result’; use ‘enum’ keyword to refer to the type
 okon_prepare_result okon_prepare(const char* input_db_file_path, const char* working_directory,
 ^~~~~~~~~~~~~~~~~~~
 enum 
<okon_root_dir>/include/okon/okon.h:62:1: error: unknown type name ‘okon_exists_result’; use ‘enum’ keyword to refer to the type
 okon_exists_result okon_exists_text(const char* sha1, const char* prepared_file_path);
 ^~~~~~~~~~~~~~~~~~
 enum 
<okon_root_dir>/include/okon/okon.h:70:1: error: unknown type name ‘okon_exists_result’; use ‘enum’ keyword to refer to the type
 okon_exists_result okon_exists_binary(const void* sha1, const char* processed_file_path);
 ^~~~~~~~~~~~~~~~~~
 enum 

Consider reworking the enum definitions in okon.h as proposed below

typedef enum abc {
   // ...
} abc;

Also consider adding some C API regression test

[stryku]

Thanks for reporting. I'll check that out tomorrow.