1 files changed, 9 insertions, 7 deletions
diff --git a/osdep/win32/include/pthread.h b/osdep/win32/include/pthread.h
index 7b82eb2651..e1324a0bb0 100644
--- a/osdep/win32/include/pthread.h
+++ b/osdep/win32/include/pthread.h
@@ -25,19 +25,21 @@
 int pthread_once(pthread_once_t *once_control, void (*init_routine)(void));
 
 typedef struct {
-    char static_mutex;
-    INIT_ONCE static_init;
-    CRITICAL_SECTION cs;
+    char use_cs;
+    union {
+        SRWLOCK srw;
+        CRITICAL_SECTION cs;
+    } lock;
 } pthread_mutex_t;
 
-#define PTHREAD_MUTEX_INITIALIZER {1, INIT_ONCE_STATIC_INIT}
+// Assume SRWLOCK_INIT is {0} so we can easily remain C89-compatible.
+#define PTHREAD_MUTEX_INITIALIZER {0}
 
 #define pthread_mutexattr_t int
 #define pthread_mutexattr_destroy(attr) (void)0
 #define pthread_mutexattr_init(attr) (*(attr) = 0)
-#define pthread_mutexattr_settype(attr, type) (void)0
-// CRITICAL_SECTION is always recursive
-#define PTHREAD_MUTEX_RECURSIVE 0
+#define pthread_mutexattr_settype(attr, type) (*(attr) = (type))
+#define PTHREAD_MUTEX_RECURSIVE 1
 
 int pthread_mutex_destroy(pthread_mutex_t *mutex);
 int pthread_mutex_init(pthread_mutex_t *restrict mutex,