g4vg: new package (#48844)

* g4vg: new package

* [@spackbot] updating style on behalf of sethrj

var/spack/repos/builtin/packages/g4vg/package.py

@@ -0,0 +1,36 @@
+# Copyright Spack Project Developers. See COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack.package import *
+
+
+class G4vg(CMakePackage):
+    """Generate VecGeom geometry representations from in-memory Geant4 geometry."""
+
+    homepage = "https://github.com/celeritas-project/g4vg"
+    url = "https://github.com/celeritas-project/g4vg/releases/download/v1.0.1/g4vg-1.0.1.tar.gz"
+
+    maintainers("sethrj", "drbenmorgan")
+
+    license("Apache-2.0", checked_by="sethrj")
+
+    version("1.0.1", sha256="add7ce4bc37889cac2101323a997cea8574b18da6cbeffdab44a2b714d134e99")
+
+    variant("debug", default=False, description="Enable runtime debug assertions")
+    variant("shared", default=True, description="Build shared libraries")
+
+    depends_on("cxx", type="build")
+    depends_on("vecgeom@1.2.8:")
+    depends_on("geant4")
+
+    def cmake_args(self):
+        define = self.define
+        from_variant = self.define_from_variant
+        args = [
+            from_variant("BUILD_SHARED_LIBS", "shared"),
+            from_variant("G4VG_DEBUG", "debug"),
+            define("G4VG_BUILD_TESTS", False),
+        ]
+
+        return args