diff --git a/src/calibre/utils/fonts/freetype.cpp b/src/calibre/utils/fonts/freetype.cpp
index afaa65371f..62314bfe2e 100644
--- a/src/calibre/utils/fonts/freetype.cpp
+++ b/src/calibre/utils/fonts/freetype.cpp
@@ -309,10 +309,9 @@ exec_module(PyObject *m) {
 
 static PyModuleDef_Slot slots[] = { {Py_mod_exec, (void*)exec_module}, {0, NULL} };
 
-static struct PyModuleDef module_def = {0};
+static struct PyModuleDef module_def = {{0}};
 
 CALIBRE_MODINIT_FUNC PyInit_freetype(void) {
-
 	module_def.m_base = PyModuleDef_HEAD_INIT;
 	module_def.m_name = "freetype";
 	module_def.m_doc = freetype_doc;
diff --git a/src/calibre/utils/spell/hunspell_wrapper.cpp b/src/calibre/utils/spell/hunspell_wrapper.cpp
index 9802e37fb5..7e48dbe2be 100644
--- a/src/calibre/utils/spell/hunspell_wrapper.cpp
+++ b/src/calibre/utils/spell/hunspell_wrapper.cpp
@@ -184,7 +184,7 @@ exec_module(PyObject *mod) {
 
 static PyModuleDef_Slot slots[] = { {Py_mod_exec, (void*)exec_module}, {0, NULL} };
 
-static struct PyModuleDef module_def = {0};
+static struct PyModuleDef module_def = {{0}};
 
 CALIBRE_MODINIT_FUNC PyInit_hunspell(void) {
 	module_def.m_base = PyModuleDef_HEAD_INIT;