do not require truffle.h on the user machine

Author: timfel

graalpython/com.oracle.graal.python.cext/include/Python.h

@@ -50,7 +50,6 @@
 #define PYPY_VERSION 0
 #define PYPY_VERSION_NUM 0
 
-#include <truffle.h>
 #include <stdio.h>
 #include <string.h>
 #include <errno.h>

graalpython/com.oracle.graal.python.cext/src/capi.h

@@ -47,6 +47,7 @@
 #include <polyglot.h>
 
 #include "Python.h"
+#include <truffle.h>
 
 #define SRC_CS "utf-8"