From 9cca022465b6bee5f766cf317c150e791f105dbe Mon Sep 17 00:00:00 2001
From: Lukas Mai <lukasmai.403@gmail.com>
Date: Wed, 31 Jul 2024 21:55:33 +0200
Subject: [PATCH] t/porting/cpphdrcheck.t: fix cc version fallback
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The `unless ($ver)` check doesn't work as intended because
`` `$cc -V 2>&1` `` captures stderr (intentionally, for Sun C). This
means with gcc or clang `$ver` ends up containing a true-ish string,
either

    gcc: error: unrecognized command-line option ‘-V’
    gcc: fatal error: no input files
    compilation terminated.

or

    clang: error: argument to '-V' is missing (expected 1 value)
    clang: error: no input files

so the `$cc --version` fallback never runs.

Checking for a non-zero exit status and the word "error" in the output
seems to work reliably, though.
---
 t/porting/cpphdrcheck.t | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/t/porting/cpphdrcheck.t b/t/porting/cpphdrcheck.t
index 88c7496b0832..861fe176d5c9 100644
--- a/t/porting/cpphdrcheck.t
+++ b/t/porting/cpphdrcheck.t
@@ -124,7 +124,7 @@ sub find_ccpp ($cc) {
         # intel C, Sun C
         # Sun C sends -V output to stderr
         my $ver = `$cc -V 2>&1`;
-        unless ($ver) {
+        if (!$ver || ($? && $ver =~ /\berror\b/)) {
             # gcc, clang
             $ver = `$cc --version 2>$devnull`;
         }