From a6bb26091a575756cb8554d3376feb52f0300f92 Mon Sep 17 00:00:00 2001
From: Oswald Buddenhagen <ossi@users.sf.net>
Date: Fri, 15 Nov 2019 20:21:50 +0100
Subject: [PATCH] modernize list of gcc warning flags somewhat

---
 configure.ac | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index a4c002d..811db2c 100644
--- a/configure.ac
+++ b/configure.ac
@@ -6,7 +6,16 @@ AM_MAINTAINER_MODE
 
 AC_PROG_CC_C99
 if test "$GCC" = yes; then
-    CFLAGS="$CFLAGS -pipe -W -Wall -Wshadow -Wstrict-prototypes -std=c99 -pedantic -Wno-overlength-strings"
+    warnings="
+        -Wall -Wextra
+        -Wshadow
+        -Wcast-qual
+        -Wformat=2 -Wformat-signedness -Wformat-nonliteral
+        -Wstrict-prototypes
+
+        -Wno-overlength-strings
+    "
+    CFLAGS="$CFLAGS -pipe -std=c99 -pedantic $(echo $warnings)"
 fi
 
 CPPFLAGS="$CPPFLAGS -D_GNU_SOURCE"