Update Kerberos/GSSAPI configure/meson check

Instead of checking for the much older gss_init_sec_context, check for
gss_store_cred_into which was added in MIT Kerberos 1.11 (circa 2012).

Discussion: https://postgr.es/m/2313469.1681695223%40sss.pgh.pa.us

Author: sfrost

configure.ac

@@ -1340,8 +1340,8 @@ fi
 
 if test "$with_gssapi" = yes ; then
   if test "$PORTNAME" != "win32"; then
-    AC_SEARCH_LIBS(gss_init_sec_context, [gssapi_krb5 gss 'gssapi -lkrb5 -lcrypto'], [],
-                   [AC_MSG_ERROR([could not find function 'gss_init_sec_context' required for GSSAPI])])
+    AC_SEARCH_LIBS(gss_store_cred_into, [gssapi_krb5 gss 'gssapi -lkrb5 -lcrypto'], [],
+                   [AC_MSG_ERROR([could not find function 'gss_store_cred_into' required for GSSAPI])])
   else
     LIBS="$LIBS -lgssapi32"
   fi

meson.build

@@ -634,14 +634,14 @@ if not gssapiopt.disabled()
   endif
 
   if not have_gssapi
-  elif cc.has_function('gss_init_sec_context', dependencies: gssapi,
+  elif cc.has_function('gss_store_cred_into', dependencies: gssapi,
       args: test_c_args, include_directories: postgres_inc)
     cdata.set('ENABLE_GSS', 1)
 
     krb_srvtab = 'FILE:/@0@/krb5.keytab)'.format(get_option('sysconfdir'))
     cdata.set_quoted('PG_KRB_SRVTAB', krb_srvtab)
   elif gssapiopt.enabled()
-    error('''could not find function 'gss_init_sec_context' required for GSSAPI''')
+    error('''could not find function 'gss_store_cred_into' required for GSSAPI''')
   else
     have_gssapi = false
   endif