Fix warnings about repeated deinitions of macros.

test/assignment_threaded.cpp

@@ -7,13 +7,10 @@
 // Public License v. 2.0. If a copy of the MPL was not distributed
 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-#if defined(EIGEN_USE_THREADS)
-#undef EIGEN_USE_THREADS
-#endif
-
-#define EIGEN_USE_THREADS
+#define EIGEN_USE_THREADS 1
 
 #include "main.h"
+#include <Eigen/ThreadPool>
 
 namespace Eigen {
 namespace internal {

test/main.h

@@ -52,9 +52,6 @@
 #if __cplusplus >= 201103L || (defined(_MSVC_LANG) && _MSVC_LANG >= 201103L)
 #include <random>
 #include <chrono>
-#ifdef EIGEN_USE_THREADS
-#include <Eigen/ThreadPool>
-#endif
 #endif
 #if __cplusplus > 201703L
 // libstdc++ 9's <memory> indirectly uses max() via <bit>.
@@ -219,11 +216,7 @@ class EigenTest {
 }  // namespace Eigen
 
 #define TRACK std::cerr << __FILE__ << " " << __LINE__ << std::endl
-// #define TRACK while()
 
-#ifdef EIGEN_DEFAULT_IO_FORMAT
-#undef EIGEN_DEFAULT_IO_FORMAT
-#endif
 #define EIGEN_DEFAULT_IO_FORMAT IOFormat(4, 0, "  ", "\n", "", "", "", "")
 
 #if (defined(_CPPUNWIND) || defined(__EXCEPTIONS)) && !defined(__CUDA_ARCH__) && !defined(__HIP_DEVICE_COMPILE__) && \