https://github.com/HDFGroup/hdf5/commit/9dd36f016a4316b94f5df15856d228de01d304c6

From 9dd36f016a4316b94f5df15856d228de01d304c6 Mon Sep 17 00:00:00 2001
From: Ryan Schmidt <ryandesign@macports.org>
Date: Thu, 17 Nov 2022 16:28:44 -0600
Subject: [PATCH] Simplify & fix check for szlib encoder (#2263)

Return the result rather than setting the exit code. "return" is a
language keyword whereas "exit" is a function for which the <stdlib.h>
header has to be included which it wasn't in this test, therefore the
test would previously fail to identify that the encoder was enabled if
"-Werror=implicit-function-declaration" was used, which it is by default
with clang from Xcode 12 and later.

Fixes #2262
--- a/configure.ac
+++ b/configure.ac
@@ -1737,10 +1737,7 @@ if test "x$HAVE_SZLIB" = "xyes" -a "x$HAVE_SZLIB_H" = "xyes"; then
                 #include "szlib.h"
             ],[[
                 /* SZ_encoder_enabled returns 1 if encoder is present */
-                if(SZ_encoder_enabled() == 1)
-                    exit(0);
-                else
-                    exit(1);
+                return SZ_encoder_enabled() != 1;
             ]])]
         , [hdf5_cv_szlib_can_encode=yes], [hdf5_cv_szlib_can_encode=no],)]
    )