io.c incompatible pointer between public.read_func and ssize_t(*)() with c23

[Jeffrey Cliff]

Configuration Information [Automatically generated, do not change]:
Machine: x86_64
OS: linux-gnm
Compiler: gcc (GCC) 15.0.0 20240509 (experimental)
Compilation CFLAGS: -std=gnu23 -DNDEBUG
uname output: Linux fatima 6.10.3-gnu-c23-qxfixgnm #2 SMP
PREEMPT_DYNAMIC Wed Aug  7 20:46:44 CST 2024 x86_64 GNU/Linux
Machine Type: x86_64-pc-linux-gnu

Gawk Version: 5.3.0*

Attestation 1:
        I have read
https://www.gnu.org/software/gawk/manual/html_node/Bugs.html.
        Yes

Attestation 2:
        I have not modified the sources before building gawk.
        True

Description:

compilation fails at io.c:

        # gcc -DDEFPATH='".:/usr/local/share/awk"'
-DDEFLIBPATH="\"/usr/local/lib/gawk\"" -DSHLIBEXT="\"so"\"
-DHAVE_CONFIG_H -DGAWK -DLOCALEDIR='"/usr/local/share/locale"'
-I"./support" -I.    -std=gnu23  -DND\
EBUG -std=gnu23  -DNDEBUG -MT io.o -MD -MP -MF $depbase.Tpo -c -o io.o io.c &&\
        mv -f $depbase.Tpo $depbase.Po
        io.c: In function 'iop_alloc':
        io.c:3389:31: error: assignment to 'ssize_t (*)(int,  void *,
size_t)' {aka 'long int (*)(int,  void *, long unsigned int)'} from
incompatible pointer type 'ssize_t (*)(void)' {aka 'long int
(*)(void)'}\
 [-Wincompatible-pointer-types]
         3389 |         iop->public.read_func = ( ssize_t(*)() ) read;
               |                               ^
               io.c: In function 'get_read_timeout':
               io.c:4449:36: warning: comparison of distinct pointer
types lacks a cast [-Wcompare-distinct-pointer-types]
                4449 |         if ((iop->public.read_func == (
ssize_t(*)() ) read) && tmout > 0)
                      |                                    ^~

Repeat-By:
        setting CFLAGS to -std=gnu23 on gcc new enough to support it

( installed gawk is 5.2.2 trying to upgrade to 5.3.0 )