From 7c9bc364f5524fcce396f5ac1afc404e33118891 Mon Sep 17 00:00:00 2001
From: Ray Speth <speth@mit.edu>
Date: Sat, 17 Oct 2015 15:52:33 -0400
Subject: [PATCH] [SCons] Add helpful error message when cppformat submodule is
 missing

---
 SConstruct | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/SConstruct b/SConstruct
index ff8afe007..346bfb281 100644
--- a/SConstruct
+++ b/SConstruct
@@ -766,6 +766,12 @@ def config_error(message):
 if not conf.CheckCXXHeader('cmath', '<>'):
     config_error('The C++ compiler is not correctly configured.')
 
+# Check that cppformat submodule is in place
+if not os.path.exists('ext/cppformat/format.h'):
+    config_error('Cppformat submodule is missing.\n'
+                 'The module can be checked out using git by running:\n\n'
+                 '    git submodule update --init --recursive\n')
+
 def get_expression_value(includes, expression):
     s = ['#include ' + i for i in includes]
     s.extend(('#define Q(x) #x',