Fix unsafe return for ossie::badConversion::what()

The return value of "c_str()" does not outlive the temporary string or
stringstream, which go out of scope at the function return. Although it's no
longer needed, the overload of "what()" remains to ensure ABI compatibility.

(see Geontech/core-framework@3ef4cd3)

Signed-off-by: Thomas Goodwin <btgoodwin@geontech.com>

Author: Thomas Goodwin

recipes-core/core-framework/redhawk-2.2.3/prop_helpers-bad-conversion.patch

@@ -0,0 +1,39 @@
+Index: src/base/include/ossie/prop_helpers.h
+===================================================================
+--- src.orig/base/include/ossie/prop_helpers.h
++++ src/base/include/ossie/prop_helpers.h
+@@ -84,15 +84,28 @@ namespace ossie
+ 
+     class badConversion : public std::runtime_error {
+     public:
+-        badConversion(std::string value, std::string type) : std::runtime_error("Unable to perform conversion"), _value(value), _type(type) {};
+-        ~badConversion() throw() {};
++        badConversion(std::string value, std::string type) :
++            std::runtime_error(badConversion::error_message(value, type)),
++            _value(value),
++            _type(type)
++        {
++        }
++
++        ~badConversion() throw() {}
++
+         virtual const char* what() const throw()
+         {
+-            std::ostringstream _msg;
+-            _msg << std::runtime_error::what() << ": '"<<_value<<"' to type '"<<_type << "'";
+-            return _msg.str().c_str();
+-        };
++            // This function is preserved to keep the vtable the same, but can
++            // be removed when ABI compatibility is not a concern.
++            return std::runtime_error::what();
++        }
+     private:
++        static std::string error_message(const std::string& value, const std::string& type)
++        {
++            std::ostringstream msg;
++            msg << "Unable to perform conversion: '" << value << "' to type '" << type << "'";
++            return msg.str();
++        }
+         std::string _value, _type;
+     };
+ 

recipes-core/core-framework/redhawk_2.2.3.bb

@@ -66,6 +66,7 @@ SRC_URI_append = "\
     file://dlopen_reverse_order.patch \
     file://bare-python2-references.patch \
     file://filesystem_impl-const-value.patch \
+    file://prop_helpers-bad-conversion.patch \
 "
 
 S = "${WORKDIR}/git/redhawk/src"