Add throw_exception_from_error overload for std::exception_ptr

include/boost/system/result.hpp

@@ -18,6 +18,7 @@
 #include <utility>
 #include <iosfwd>
 #include <system_error>
+#include <exception>
 
 //
 
@@ -53,6 +54,18 @@ BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( std::errc
     boost::throw_with_location( std::system_error( make_error_code( e ) ), loc );
 }
 
+BOOST_NORETURN BOOST_NOINLINE inline void throw_exception_from_error( std::exception_ptr const & p, boost::source_location const& loc )
+{
+    if( p )
+    {
+        std::rethrow_exception( p );
+    }
+    else
+    {
+        boost::throw_with_location( std::bad_exception(), loc );
+    }
+}
+
 #if defined(__GNUC__) && __GNUC__ >= 7 && __GNUC__ <= 8
 # pragma GCC diagnostic pop
 #endif