Preserve errno before closing files to prevent it from being overwritten

Author: yasir-hussain-shah

contrib/ivorysql_ora/src/builtin_packages/utl_file/utl_file.c

@@ -529,7 +529,10 @@ ora_utl_file_fcopy(PG_FUNCTION_ARGS)
 	fclose(dstfile);
 
 	if (copy_result)
+	{
+		errno = copy_result;
 		IO_EXCEPTION();
+	}
 
 	PG_RETURN_VOID();
 }