Get rid of EIGEN_TEST_FUNC, unit tests must now be declared with EIGEN_DECLARE_TEST(mytest) { /* code */ }.

This provide several advantages:
- more flexibility in designing unit tests
- unit tests can be glued to speed up compilation
- unit tests are compiled with same predefined macros, which is a requirement for zapcc

test/spqr_support.cpp

@@ -57,7 +57,7 @@ template<typename Scalar> void test_spqr_scalar()
   refX = dA.colPivHouseholderQr().solve(b);
   VERIFY(x.isApprox(refX,test_precision<Scalar>()));
 }
-void test_spqr_support()
+EIGEN_DECLARE_TEST(spqr_support)
 {
   CALL_SUBTEST_1(test_spqr_scalar<double>());
   CALL_SUBTEST_2(test_spqr_scalar<std::complex<double> >());