[vte] build: Add -Wstrict-null-sentinel to CXXFLAGS

[Christian Persch <chpe src gnome org>]

commit 5351f75712fa62dc0016d0cece4b212b5dd43ece
Author: Christian Persch <chpe gnome org>
Date:   Mon Feb 29 18:20:27 2016 +0100

    build: Add -Wstrict-null-sentinel to CXXFLAGS
    
    https://bugzilla.gnome.org/show_bug.cgi?id=762863

 configure.ac |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c1f772c..9c1106f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -153,6 +153,7 @@ m4_define([compiler_flags_only_c],[ dnl
 ])
 
 m4_define([compiler_flags_only_cxx],[ dnl
+  -Wstrict-null-sentinel dnl
   -fno-rtti dnl
   -fno-exceptions dnl
   -fvisibility=hidden dnl