CFLAGS="-std=c23" ./configure && make

[...]
dpp: /home/dima/software/ecl/src/c/read.d -> read.o.c
[...]
/home/dima/software/ecl/src/c/read.d: In function ‘init_read’:
/home/dima/software/ecl/src/c/read.d:2023:39: error: passing argument 1 of ‘ecl_make_cfun’ from incompatible pointer type [-Wincompatible-pointer-types]
 2023 | #define make_cf3(f)     ecl_make_cfun((f), ECL_NIL, NULL, 3)
      |                                       ^~~
      |                                       |
      |                                       union cl_lispunion * (*)(union cl_lispunion *, union cl_lispunion *)
/home/dima/software/ecl/src/c/read.d:2047:29: note: in expansion of macro ‘make_cf2’
 2047 | 
      |                             ^       
In file included from /home/dima/software/ecl/build/ecl/ecl.h:82,
                 from /home/dima/software/ecl/src/c/read.d:16:
/home/dima/software/ecl/build/ecl/external.h:427:58: note: expected ‘cl_objectfn_fixed’ {aka ‘union cl_lispunion * (*)(void)’} but argument is of type ‘union cl_lispunion * (*)(union cl_lispunion *, union cl_lispunion *)’
  427 | extern ECL_API cl_object ecl_make_cfun(cl_objectfn_fixed c_function, cl_object name, cl_object block, int narg);
      |                                        ~~~~~~~~~~~~~~~~~~^~~~~~~~~~