fix various compilations issues

unsupported/Eigen/AdolcForward

@@ -114,6 +114,7 @@ template<> struct NumTraits<adtl::adouble>
     IsComplex = 0,
     IsInteger = 0,
     IsSigned = 1,
+    RequireInitialization = 1,
     ReadCost = 1,
     AddCost = 1,
     MulCost = 1

unsupported/test/mpreal_support.cpp

@@ -1,5 +1,7 @@
 #include "main.h"
 #include <Eigen/MPRealSupport>
+#include <Eigen/LU>
+#include <Eigen/Eigenvalues>
 
 using namespace mpfr;
 using namespace std;