strumpack +rocm: set CMAKE_CXX_COMPILER to hipcc (#35153)

* strumpack +rocm: set CMAKE_CXX_COMPILER to hipcc

* strumpack@7.0.1+rocm^mpich: patch in upstream commit

var/spack/repos/builtin/packages/strumpack/package.py

@@ -98,6 +98,9 @@ class Strumpack(CMakePackage, CudaPackage, ROCmPackage):
     patch("intel-19-compile.patch", when="@3.1.1")
     patch("shared-rocm.patch", when="@5.1.1")
 
+    # https://github.com/pghysels/STRUMPACK/commit/e4b110b2d823c51a90575b77ec1531c699097a9f
+    patch("strumpack-7.0.1-mpich-hipcc.patch", when="@7.0.1 +rocm ^mpich")
+
     def cmake_args(self):
         spec = self.spec
 
@@ -146,6 +149,7 @@ def cmake_args(self):
                 args.append("-DCUDA_NVCC_FLAGS={0}".format(" ".join(self.cuda_flags(cuda_archs))))
 
         if "+rocm" in spec:
+            args.append("-DCMAKE_CXX_COMPILER={0}".format(spec["hip"].hipcc))
             args.append("-DHIP_ROOT_DIR={0}".format(spec["hip"].prefix))
             rocm_archs = spec.variants["amdgpu_target"].value
             hipcc_flags = []

var/spack/repos/builtin/packages/strumpack/strumpack-7.0.1-mpich-hipcc.patch

@@ -0,0 +1,26 @@
+diff -ruN spack-src/CMakeLists.txt spack-src-patched/CMakeLists.txt
+--- spack-src/CMakeLists.txt	2022-10-12 11:48:07.000000000 -0700
++++ spack-src-patched/CMakeLists.txt	2023-01-30 13:35:11.271496106 -0800
+@@ -586,7 +586,8 @@
+ 
+ if(STRUMPACK_USE_MPI)
+   target_link_libraries(strumpack PUBLIC
+-    MPI::MPI_CXX MPI::MPI_C MPI::MPI_Fortran)
++    MPI::MPI_CXX MPI::MPI_C ${MPI_Fortran_LIBRARIES})
++  ## adding the MPI::MPI_Fortran target risks adding unwanted compile flags
+ endif()
+ 
+ if(OpenMP_FOUND)
+@@ -654,11 +655,7 @@
+     ButterflyPACK::sbutterflypack
+     ButterflyPACK::dbutterflypack
+     ButterflyPACK::cbutterflypack
+-    ButterflyPACK::zbutterflypack
+-    MPI::MPI_Fortran ${MPI_Fortran_LIBRARIES})
+-  ## for some reason just adding the MPI::MPI_Fortran target only
+-  ## links with the f08 module, not with the regular fortran MPI
+-  ## library
++    ButterflyPACK::zbutterflypack)
+ endif()
+ 
+ if(slate_FOUND)