mdspan: new package (#40024)

* new package mdspan

* Update var/spack/repos/builtin/packages/mdspan/package.py

Co-authored-by: Alec Scott <alec@bcs.sh>

* mdspan- fix style

---------

Co-authored-by: Alec Scott <alec@bcs.sh>

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

@@ -0,0 +1,44 @@
+# Copyright 2013-2022 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+
+from spack.package import *
+
+
+class Mdspan(CMakePackage):
+    """Extension of std::span to enable multidimensional arrays"""
+
+    homepage = "https://github.com/kokkos/mdspan/tree/stable"
+    url = "https://github.com/kokkos/mdspan/archive/refs/tags/mdspan-0.6.0.zip"
+    git = "https://github.com/kokkos/mdspan.git"
+
+    version("stable", branch="stable")
+    version("0.6.0", sha256="d6b7b9d4f472106df1d28729bd8383a8a7ea7938adf9f82d3be9c151344830d9")
+
+    variant("examples", default=True, description="Enable examples")
+    variant("tests", default=False, description="Enable tests")
+    variant("benchmarks", default=False, description="Enable benchmarks")
+
+    depends_on("benchmark", when="+benchmarks")
+    depends_on("googletest@main", when="+tests")
+
+    def cmake_args(self):
+        args = []
+
+        if self.spec.satisfies("+tests"):
+            args.append("-DMDSPAN_ENABLE_TESTS=ON")
+            args.append("-DMDSPAN_USE_SYSTEM_GTEST=ON")
+        if self.spec.satisfies("+bencmarks"):
+            args.append("-DMDSPAN_ENABLE_BENCHMARKS=ON")
+        if self.spec.satisfies("+examples"):
+            args.append("-DMDSPAN_ENABLE_EXAMPLES=ON")
+
+        args.append("-DCMAKE_CXX_FLAGS='-Wall -Wextra -pedantic'")
+        args.append("-DCMAKE_CXX_STANDARD=17")
+        args.append("-DMDSPAN_CXX_STANDARD=17")
+        args.append("-DCMAKE_CXX_COMPILER=g++")
+        args.append("-DCMAKE_CXX_EXTENSIONS=OFF")
+
+        return args