From 6240e4458cdf5a17c7b795def33b81cb5a987aed Mon Sep 17 00:00:00 2001
From: =?utf8?q?Thomas=20Wei=C3=9Fschuh?= <thomas@t-8ch.de>
Date: Thu, 30 Nov 2023 23:24:37 +0100
Subject: [PATCH] build: use -std=c99 and -std=c++11 by default
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Relying on the compiler default is problematic:

* New constructs may be introduced accidentally that break backwards
  compatibility.
* Older compilers may default to a more restricted standard than the
  codebase is actually developed with.

Explicitly select C99 (and C++11 for the fuzzing part).

Autotools does not want to default to C99, so set it explcitly during
CI.

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
---
 .github/workflows/cibuild.sh | 4 ++--
 meson.build                  | 6 +++++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/cibuild.sh b/.github/workflows/cibuild.sh
index bd77c053d7..be466daa25 100755
--- a/.github/workflows/cibuild.sh
+++ b/.github/workflows/cibuild.sh
@@ -5,8 +5,8 @@ set -ex
 PHASES=(${@:-CONFIGURE MAKE INSTALL CHECK DISTCHECK})
 COMPILER="${COMPILER:?}"
 COMPILER_VERSION="${COMPILER_VERSION}"
-CFLAGS=(-O1 -g)
-CXXFLAGS=(-O1 -g)
+CFLAGS=(-O1 -g -std=c99)
+CXXFLAGS=(-O1 -g -std=c++11)
 LDFLAGS=()
 COVERITY_SCAN_TOOL_BASE="/tmp/coverity-scan-analysis"
 
diff --git a/meson.build b/meson.build
index fb2818a5d3..331d758298 100644
--- a/meson.build
+++ b/meson.build
@@ -1,7 +1,11 @@
 project('util-linux', 'c',
         version : run_command('tools/git-version-gen', check: true).stdout(),
         meson_version: '>=0.60.0',
-        license : 'GPLv2+')
+        license : 'GPLv2+',
+        default_options : [
+          'c_std=c99',
+          'cpp_std=c++11',
+        ])
 
 fs = import('fs')
 pkgconfig = import('pkgconfig')
-- 
2.47.3