diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index 0dc06cc9d4d3ae..56f3306e6c88a8 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -959,7 +959,7 @@ getattributelist(PyObject *obj, const char *name, AttributeList *attribute_list)
     DWORD err;
     BOOL result;
     PyObject *value;
-    Py_ssize_t handle_list_size;
+    Py_ssize_t handle_list_size = 0;
     DWORD attribute_count = 0;
     SIZE_T attribute_list_size = 0;
 
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index e5d724fee8ddb1..d6530e1ef89473 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -5490,7 +5490,7 @@ os_utime_impl(PyObject *module, path_t *path, PyObject *times, PyObject *ns,
 /*[clinic end generated code: output=cfcac69d027b82cf input=2fbd62a2f228f8f4]*/
 {
 #ifdef MS_WINDOWS
-    HANDLE hFile;
+    HANDLE hFile = 0;
     FILETIME atime, mtime;
 #else
     int result;
@@ -14705,7 +14705,7 @@ os__add_dll_directory_impl(PyObject *module, path_t *path)
        loaded. */
     Py_BEGIN_ALLOW_THREADS
     if (!(hKernel32 = GetModuleHandleW(L"kernel32")) ||
-        !(AddDllDirectory = (PAddDllDirectory)GetProcAddress(
+        !(AddDllDirectory = (PAddDllDirectory)(void *)GetProcAddress(
             hKernel32, "AddDllDirectory")) ||
         !(cookie = (*AddDllDirectory)(path->wide))) {
         err = GetLastError();
@@ -14755,7 +14755,7 @@ os__remove_dll_directory_impl(PyObject *module, PyObject *cookie)
        loaded. */
     Py_BEGIN_ALLOW_THREADS
     if (!(hKernel32 = GetModuleHandleW(L"kernel32")) ||
-        !(RemoveDllDirectory = (PRemoveDllDirectory)GetProcAddress(
+        !(RemoveDllDirectory = (PRemoveDllDirectory)(void *)GetProcAddress(
             hKernel32, "RemoveDllDirectory")) ||
         !(*RemoveDllDirectory)(cookieValue)) {
         err = GetLastError();
diff --git a/Modules/socketmodule.h b/Modules/socketmodule.h
index 1b35b11cdee6af..cff1f1d054fd30 100644
--- a/Modules/socketmodule.h
+++ b/Modules/socketmodule.h
@@ -68,8 +68,10 @@ struct SOCKADDR_BTH_REDEF {
  */
 # ifdef SIO_GET_MULTICAST_FILTER
 #  include <mstcpip.h> /* for SIO_RCVALL */
+#ifndef __MINGW32__ /* resolve by configure */
 #  define HAVE_ADDRINFO
 #  define HAVE_SOCKADDR_STORAGE
+#endif
 #  define HAVE_GETADDRINFO
 #  define HAVE_GETNAMEINFO
 #  define ENABLE_IPV6
diff --git a/PC/python_exe.rc b/PC/python_exe.rc
index c3d3bff019895e..dde0e5384201fa 100644
--- a/PC/python_exe.rc
+++ b/PC/python_exe.rc
@@ -12,7 +12,7 @@
 // current versions of Windows.
 1 RT_MANIFEST "python.manifest"
 
-1 ICON DISCARDABLE "icons\python.ico" 
+1 ICON DISCARDABLE "icons/python.ico"
 
 
 /////////////////////////////////////////////////////////////////////////////
diff --git a/PC/pythonw_exe.rc b/PC/pythonw_exe.rc
index 38570b74fa3e02..7ce1043298eac4 100644
--- a/PC/pythonw_exe.rc
+++ b/PC/pythonw_exe.rc
@@ -12,7 +12,7 @@
 // current versions of Windows.
 1 RT_MANIFEST "python.manifest"
 
-1 ICON DISCARDABLE "icons\pythonw.ico" 
+1 ICON DISCARDABLE "icons/pythonw.ico"
 
 
 /////////////////////////////////////////////////////////////////////////////
diff --git a/PC/winreg.c b/PC/winreg.c
index 0850cec60f716f..08548a7d6b299e 100644
--- a/PC/winreg.c
+++ b/PC/winreg.c
@@ -825,6 +825,7 @@ Reg2Py(BYTE *retDataBuf, DWORD retDataSize, DWORD typ)
         case REG_BINARY:
         /* ALSO handle ALL unknown data types here.  Even if we can't
            support it natively, we should handle the bits. */
+           /* fallthrough */
         default:
             if (retDataSize == 0) {
                 Py_INCREF(Py_None);
diff --git a/Python/thread_nt.h b/Python/thread_nt.h
index 084bd587314876..f8a6765280c722 100644
--- a/Python/thread_nt.h
+++ b/Python/thread_nt.h
@@ -360,8 +360,9 @@ PyThread_release_lock(PyThread_type_lock aLock)
 {
     dprintf(("%lu: PyThread_release_lock(%p) called\n", PyThread_get_thread_ident(),aLock));
 
-    if (!(aLock && LeaveNonRecursiveMutex((PNRMUTEX) aLock)))
+    if (!(aLock && LeaveNonRecursiveMutex((PNRMUTEX) aLock))) {
         dprintf(("%lu: Could not PyThread_release_lock(%p) error: %ld\n", PyThread_get_thread_ident(), aLock, GetLastError()));
+    }
 }
 
 /* minimum/maximum thread stack sizes supported */