Fix macOS build

std::srand was not existing maybe an issue with older SDKs.

Change-Id: Icd1af82d6e698da9f814ed0d96a839f46272c661
Reviewed-by: Orgad Shaneh <orgads@gmail.com>

src/plugins/coreplugin/coreplugin.cpp

@@ -65,6 +65,8 @@
 #include <QMenu>
 #include <QUuid>
 
+#include <cstdlib>
+
 using namespace Core;
 using namespace Core::Internal;
 using namespace Utils;