From 0bd1e0d6ebfcc273a725d9d9231eedd26a6129fd Mon Sep 17 00:00:00 2001
From: Oliver Smith <osmith@sysmocom.de>
Date: Thu, 19 Oct 2023 15:41:39 +0200
Subject: [PATCH] configure: add --enable-werror

Change-Id: Ife3716c667d2e9b3fcd94d3cdc044d594e7dab5a
---
 configure.ac | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/configure.ac b/configure.ac
index e7d9888..a16f40b 100644
--- a/configure.ac
+++ b/configure.ac
@@ -53,6 +53,25 @@ then
 	CPPFLAGS="$CPPFLAGS -fsanitize=address -fsanitize=undefined"
 fi
 
+AC_ARG_ENABLE(werror,
+	[AS_HELP_STRING(
+		[--enable-werror],
+		[Turn all compiler warnings into errors, with exceptions:
+		 a) deprecation (allow upstream to mark deprecation without breaking builds);
+		 b) "#warning" pragmas (allow to remind ourselves of errors without breaking builds)
+		]
+	)],
+	[werror=$enableval], [werror="no"])
+if test x"$werror" = x"yes"
+then
+	WERROR_FLAGS="-Werror"
+	WERROR_FLAGS+=" -Werror=implicit-int -Werror=int-conversion -Werror=old-style-definition"
+	WERROR_FLAGS+=" -Wno-error=deprecated -Wno-error=deprecated-declarations"
+	WERROR_FLAGS+=" -Wno-error=cpp" # "#warning"
+	CFLAGS="$CFLAGS $WERROR_FLAGS"
+	CPPFLAGS="$CPPFLAGS $WERROR_FLAGS"
+fi
+
 AC_SUBST([CPPFLAGS])
 AC_SUBST([CFLAGS])
 AC_CONFIG_FILES([Makefile src/Makefile include/Makefile include/libgtpnl/Makefile include/linux/Makefile tools/Makefile libgtpnl.pc])