[master] b440f850b build: Invoke wflags.py as configured

[Dridi Boukelmoune]

commit b440f850be34604ccb2e70b59f529aee45e98b7a
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Tue Mar 30 13:55:22 2021 +0200

    build: Invoke wflags.py as configured

diff --git a/configure.ac b/configure.ac
index 8bad83f6b..de24d8ceb 100644
--- a/configure.ac
+++ b/configure.ac
@@ -718,7 +718,7 @@ AX_CHECK_COMPILE_FLAG([-Werror=unused-result],
       OCFLAGS="${OCFLAGS} -Wno-unused-result"])])
 
 # This corresponds to FreeBSD's WARNS level 6
-DEVELOPER_CFLAGS=`python3 wflags.py`
+DEVELOPER_CFLAGS=`$PYTHON $srcdir/wflags.py`
 
 # --enable-stack-protector
 AC_ARG_ENABLE(stack-protector,