Fix for #964 from DAP

git-svn-id: https://svn.code.sf.net/p/speed-dreams/code/trunk@6440 30fe4595-0a0c-4342-8851-515496e4dcbd

Former-commit-id: 92616d0eab9a05dec38e2978f7eb70fb2551199b
Former-commit-id: a7003f74d1617ef5670bea5dc8225cbe25c3ee63

src/libs/learning/policy.cpp

@@ -18,6 +18,12 @@
 #include "MathFunctions.h"
 #ifdef WIN32
 #include <float.h>
+#else
+// std::isnan should be available as of C++11 (201103L) but some compiler 
+// vendors set this even though support is incomplete
+#if __cplusplus>=201402L // compiler claims to be C++14 compliant
+#define isnan std::isnan
+#endif
 #endif // WIN32
 
 #include <portability.h>