[wince] Two more Windows CE fixes

Report has it that it builds (and works) now:

  https://codereview.qt-project.org/#/c/92087/

src/hb-mutex-private.hh

diff --git a/src/hb-mutex-private.hh b/src/hb-mutex-private.hh
index eaa2169..6281201 100644
--- a/src/hb-mutex-private.hh
+++ b/src/hb-mutex-private.hh
@@ -46,7 +46,7 @@
 
 #include <windows.h>
 typedef CRITICAL_SECTION hb_mutex_impl_t;
-#define HB_MUTEX_IMPL_INIT	{ NULL, 0, 0, NULL, NULL, 0 }
+#define HB_MUTEX_IMPL_INIT	{0}
 #define hb_mutex_impl_init(M)	InitializeCriticalSection (M)
 #define hb_mutex_impl_lock(M)	EnterCriticalSection (M)
 #define hb_mutex_impl_unlock(M)	LeaveCriticalSection (M)

src/hb-private.hh

diff --git a/src/hb-private.hh b/src/hb-private.hh
index 2709c0e..ab18274 100644
--- a/src/hb-private.hh
+++ b/src/hb-private.hh
@@ -96,6 +96,8 @@
 
 #if (defined(__WIN32__) && !defined(__WINE__)) || defined(_MSC_VER)
 #define snprintf _snprintf
+/* Windows CE only has _strdup, while rest of Windows has both. */
+#define strdup _strdup
 #endif
 
 #ifdef _MSC_VER