BUG #18995: Building with GCC 14 fails: incompatible pointer struct pam_message

The following bug has been logged on the website:

Bug reference:      18995
Logged by:          Andrew Watkins
Email address:      awatkins1966@gmail.com
PostgreSQL version: 17.5
Operating system:   Solaris 11.4
Description:

Hello,
Not sure if a Oracle Solaris problem or not.

First, PostgreSQL 17.5 with GCC v13 builds cleaning and runs on Solaris
11.4, but building with GCC v14 I get the following:

gcc -m64 -Wall -Wmissing-prototypes -Wpointer-arith
-Wdeclaration-after-statement -Werror=vla -Wendif-labels
-Wmissing-format-attribute -Wimplicit-fallthrough=3 -Wcast-function-type
-Wshadow=compatible-local -Wformat-security -fno-strict-aliasing -fwrapv
-fexcess-precision=standard -Wno-format-truncation -Wno-stringop-truncation
-O2 -I../../../src/include  -D_POSIX_PTHREAD_SEMANTICS
-I/usr/include/libxml2   -c -o auth.o auth.c
auth.c:101:9: error: initialization of 'int (*)(int,  struct pam_message **,
struct pam_response **, void *)' from incompatible pointer type 'int
(*)(int,  const struct pam_message **, struct pam_response **, void *)'
[-Wincompatible-pointer-types]
  101 |         &pam_passwd_conv_proc,
      |         ^
auth.c:101:9: note: (near initialization for 'pam_passw_conv.conv')
gmake[3]: *** [<builtin>: auth.o] Error 1
gmake[3]: Leaving directory
'/home/andrew/src/postgresql-17.5/src/backend/libpq'
gmake[2]: *** [common.mk:37: libpq-recursive] Error 2
gmake[2]: Leaving directory '/home/andrew/src/postgresql-17.5/src/backend'
gmake[1]: *** [Makefile:42: all-backend-recurse] Error 2
gmake[1]: Leaving directory '/home/andrew/src/postgresql-17.5/src'
gmake: *** [GNUmakefile:11: all-src-recurse] Error 2

Thanks,
Andrew