Move definition of bv_encodingt into separate file

So that the parsing code can be separated from `configt`.

Author: thomasspriggs

src/util/bv_encoding.h

@@ -0,0 +1,23 @@
+/*******************************************************************\
+
+Module: bv_encoding configuration
+
+Author: Diffblue Ltd
+
+\*******************************************************************/
+
+#ifndef CPROVER_UTIL_BV_ENCODING_H
+#define CPROVER_UTIL_BV_ENCODING_H
+
+#include <cstddef>
+
+struct bv_encodingt
+{
+  // number of bits to encode heap object addresses
+  std::size_t object_bits;
+  bool is_object_bits_default;
+
+  static const std::size_t default_object_bits = 8;
+};
+
+#endif // CPROVER_UTIL_BV_ENCODING_H

src/util/config.h

@@ -12,6 +12,7 @@ Author: Daniel Kroening, [email protected]
 
 #include <list>
 
+#include "bv_encoding.h"
 #include "ieee_float.h"
 #include "irep.h"
 #include "optional.h"
@@ -170,14 +171,7 @@ class configt
     static const std::size_t default_object_bits=16;
   } java;
 
-  struct bv_encodingt
-  {
-    // number of bits to encode heap object addresses
-    std::size_t object_bits;
-    bool is_object_bits_default;
-
-    static const std::size_t default_object_bits=8;
-  } bv_encoding;
+  bv_encodingt bv_encoding;
 
   // this is the function to start executing
   optionalt<std::string> main;