[master] b28f6143f build: Error out of configure if wflags.py fails

[Nils Goroll]

commit b28f6143febd2bd143b1c9cbb930e0bba716362c
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Thu Jun 10 15:41:40 2021 +0200

    build: Error out of configure if wflags.py fails
    
    Fixes #3624

diff --git a/configure.ac b/configure.ac
index 3e02d06d0..553e9f43d 100644
--- a/configure.ac
+++ b/configure.ac
@@ -719,6 +719,9 @@ AX_CHECK_COMPILE_FLAG([-Werror=unused-result],
 
 # This corresponds to FreeBSD's WARNS level 6
 DEVELOPER_CFLAGS=`$PYTHON $srcdir/wflags.py`
+if test $? -ne 0 ; then
+  AC_MSG_ERROR([wflags.py failure])
+fi
 
 # --enable-stack-protector
 AC_ARG_ENABLE(stack-protector,