fixed: don't use thread::sleep_for where it's known to be broken

Fixes #2690.

src/util.h

@@ -105,7 +105,11 @@ T* alignup(T* p)
 
 inline void MilliSleep(int64 n)
 {
-#if BOOST_VERSION >= 105000
+// Boost's sleep_for was uninterruptable when backed by nanosleep from 1.50
+// until fixed in 1.52. Use the deprecated sleep method for the broken case.
+// See: https://svn.boost.org/trac/boost/ticket/7238
+
+#if BOOST_VERSION >= 105000 && (!defined(BOOST_HAS_NANOSLEEP) || BOOST_VERSION >= 105200)
     boost::this_thread::sleep_for(boost::chrono::milliseconds(n));
 #else
     boost::this_thread::sleep(boost::posix_time::milliseconds(n));