Created attachment 1937299 [details]
tkgate-c99.patch

I tried to port the package to C99 mode, but failed because of internal type conflicts.

With the attached patch, I get:

In file included from tkgate.h:52,
                 from paux.c:23:
tkgate_config.h:32: note: this is the location of the previous definition
   32 | #define STRMAX          1024            /* Maximum length of a string */
      | 
paux.c:41:15: error: conflicting types for 'Encoder'; have 'void *'
   41 | typedef void *Encoder;
      |               ^~~~~~~
In file included from tkgate.h:53:
tkgate_misc.h:47:28: note: previous declaration of 'Encoder' with type 'Encoder' {aka 'struct encoder_str'}
   47 | typedef struct encoder_str Encoder;
      |                            ^~~~~~~
paux.c: In function 'ycString':