Merge branch 'upstream-diy2' into update-diy-use-internal-fmt

# By Diy2 Upstream
* upstream-diy2:
  diy2 2025-03-12 (cb906317)

ThirdParty/diy2/vtkdiy2/README.kitware.md

@@ -6,3 +6,6 @@ into another source tree.
 
   * Add attributes to pass commit checks within VTK.
   * Add a CMake file to install headers into VTK's install tree.
+  * Use VTK's MPI library.
+  * Use VTK's fmt library.
+  * Definition of template functions in header files should be inline.

ThirdParty/diy2/vtkdiy2/include/vtkdiy2/log.hpp

@@ -4,8 +4,9 @@
 #ifndef DIY_USE_SPDLOG
 
 #include <memory>
-#include "thirdparty/fmt/format.h"
-#include "thirdparty/fmt/ostream.h"
+#include "vtk_fmt.h"
+#include VTK_FMT(fmt/format.h)
+#include VTK_FMT(fmt/ostream.h)
 
 namespace diy
 {

ThirdParty/diy2/vtkdiy2/include/vtkdiy2/mpi/mpi_cast.hpp

@@ -5,7 +5,7 @@
 /// to thier correct types.
 
 #ifndef DIY_HAS_MPI
-#  include <mpi.h>
+#  include <vtk_mpi.h>
 #endif
 
 namespace diy