Issue 224: cleaning setting string empty (#229)

* cleaning setting string enpty

* apply arguments

Author: jkotan

setup.py

@@ -162,7 +162,7 @@ def add_filters(filters, pkgs, pkgs_data):
     # no-lto to be on the save side
     arguments = ['-std=c++17', '-Wall', '-Wextra', '-fdiagnostics-show-option',
                  '-fno-lto']
-    nexus_config.add_compiler_arguments(arguments)
+nexus_config.add_compiler_arguments(arguments)
 
 # ----------------------------------------------------------------------------
 # creating the extension factories

src/cpp/h5cpp/numpy/hdf5_variable_strings_support.hpp

@@ -119,14 +119,12 @@ struct VarLengthStringTrait<numpy::ArrayAdapter>
       PyObject *ptr;
       if(string == NULL)
 	{
-	  char empty[] = {'\0'};
-	  string = empty;
 #if PY_VERSION_HEX >= 0x030d0000
 	  ptr = Py_GetConstant(Py_CONSTANT_EMPTY_STR);
 #elif PY_MAJOR_VERSION >= 3
-	  ptr = PyUnicode_FromString(string);
+	  ptr = PyUnicode_FromString("");
 #else
-	  ptr = PyString_FromString(string);
+	  ptr = PyString_FromString("");
 #endif
 	}
       else