fix build with MSVC

Maximilien Siavelis

2019-05-06 681ed087b6e061966afdbe3a0a837940c643fd6d

 src/library/base/StringUtils.cpp

@@ -11,8 +11,9 @@
#include <string>
#include <cstring>
#include <algorithm>
#include <stdexcept>

#ifdef WIN32
#ifdef _WIN32
#include <time.h> //mktime under windows
#endif