copy constructors for exception classes

C++11 15.1 §5 requires that objects that are thrown have an accessible
copy/move constructor and a destructor.

This adds an explicit copy constructor to a few classes where the compiler
cannot build the default copy constructor.

Author: kroening

src/solvers/smt2/smt2_tokenizer.h

@@ -24,6 +24,15 @@ class smt2_tokenizert
   class smt2_errort
   {
   public:
+    smt2_errort(smt2_errort &&) = default;
+
+    smt2_errort(const smt2_errort &other)
+    {
+      // ostringstream does not have a copy constructor
+      message << other.message.str();
+      line_no = other.line_no;
+    }
+
     smt2_errort(const std::string &_message, unsigned _line_no)
       : line_no(_line_no)
     {

src/util/typecheck.h

@@ -25,6 +25,15 @@ class typecheckt:public messaget
   class errort final
   {
   public:
+    errort() = default;
+    errort(errort &&) = default;
+    errort(const errort &other)
+    {
+      // ostringstream does not have a copy constructor
+      message << other.message.str();
+      __location = other.__location;
+    }
+
     std::string what() const
     {
       return message.str();