msys2: fix build (#3818)

* cmake: fix mingw-w64 build

* time.cpp: fix build with Clang on Windows

* tls.h: include malloc.h for alloca

src/core/tls.h

@@ -5,6 +5,9 @@
 
 #include <cstring>
 #include "common/types.h"
+#ifdef _WIN32
+#include <malloc.h>
+#endif
 
 namespace Xbyak {
 class CodeGenerator;