diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9ac67f49..ec07594f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,8 @@
 All notable changes to this project will be documented in this file.
 
 ## Unlreleased - ???
+- Fix some marshalling bugs.
+- Add optional Makefile target to install jpm as well.
 - Supervisor channels in threads will no longer include a wastful copy of the fiber in every
   message across a thread.
 - Allow passing a closure to `ev/thead` as well as a whole fiber.
diff --git a/src/core/abstract.c b/src/core/abstract.c
index e5857daf..55ee0dad 100644
--- a/src/core/abstract.c
+++ b/src/core/abstract.c
@@ -94,19 +94,19 @@ static int32_t janet_decref(JanetAbstractHead *ab) {
 }
 
 void janet_os_mutex_init(JanetOSMutex *mutex) {
-    InitializeCriticalSection(mutex);
+    InitializeCriticalSection((CRITICAL_SECTION *) mutex);
 }
 
 void janet_os_mutex_deinit(JanetOSMutex *mutex) {
-    DeleteCriticalSection(mutex);
+    DeleteCriticalSection((CRITICAL_SECTION *) mutex);
 }
 
 void janet_os_mutex_lock(JanetOSMutex *mutex) {
-    EnterCriticalSection(mutex);
+    EnterCriticalSection((CRITICAL_SECTION *) mutex);
 }
 
 void janet_os_mutex_unlock(JanetOSMutex *mutex) {
-    LeaveCriticalSection(mutex);
+    LeaveCriticalSection((CRITICAL_SECTION *) mutex);
 }
 
 #else
diff --git a/src/include/janet.h b/src/include/janet.h
index d8e17351..f65a6a87 100644
--- a/src/include/janet.h
+++ b/src/include/janet.h
@@ -330,11 +330,16 @@ typedef struct {
 /* Some extra includes if EV is enabled */
 #ifdef JANET_EV
 #ifdef JANET_WINDOWS
-#ifdef JANET_NET
-#include <winsock2.h>
-#endif
-#include <windows.h>
-typedef CRITICAL_SECTION JanetOSMutex;
+typedef struct JanetDudCriticalSection {
+    /* Avoid including windows.h here - instead, create a structure of the same size */
+    /* Needs to be same size as crtical section see WinNT.h for CRITCIAL_SECTION definition */
+    void *debug_info;
+    long lock_count
+    long recursion_count;
+    void *owning_thread;
+    void *lock_semaphore;
+    unsigned long spin_count;
+} JanetOSMutex;
 #else
 #include <pthread.h>
 typedef pthread_mutex_t JanetOSMutex;