diff --git a/Makefile b/Makefile
index a4d3b7d964abb3a389c60fd9160b71d056b24e48..c2ae2b26511e0355fef167a53eacb002db0f1d2a 100644
--- a/Makefile
+++ b/Makefile
@@ -2,6 +2,10 @@
 
 # you will need to set the BINARY_C variable to point
 # to the root binary_c directory
+ifeq ($(BINARY_C),)
+  $(error BINARY_C is not set)
+endif
+
 
 CC      := gcc
 LD      := gcc
diff --git a/build/temp.linux-x86_64-3.6/binary_c_python.o b/build/temp.linux-x86_64-3.6/binary_c_python.o
index ca9e7c36ab4089a52d0b5498471952e18df97964..931bef1273d1cdd3d3e69442b345fbdbaedc611c 100644
Binary files a/build/temp.linux-x86_64-3.6/binary_c_python.o and b/build/temp.linux-x86_64-3.6/binary_c_python.o differ