add magma variant to strumpack (#39224)

* add magma variant to strumpack
* clarify conflicts to be excuive to rocm/cuda, without it +magma+cuda fails as it is ~rocm
   modified:   var/spack/repos/builtin/packages/strumpack/package.py
* add missing depends_on for magma variant

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

@@ -61,6 +61,7 @@ class Strumpack(CMakePackage, CudaPackage, ROCmPackage):
     variant("count_flops", default=False, description="Build with flop counters")
     variant("task_timers", default=False, description="Build with timers for internal routines")
     variant("slate", default=True, description="Build with SLATE support")
+    variant("magma", default=False, description="Build with MAGMA support")
 
     depends_on("cmake@3.11:", when="@:6.2.9", type="build")
     depends_on("cmake@3.17:", when="@6.3.0:", type="build")
@@ -84,6 +85,8 @@ class Strumpack(CMakePackage, CudaPackage, ROCmPackage):
     depends_on("rocsolver", when="+rocm")
     depends_on("rocthrust", when="+rocm")
     depends_on("slate", when="+slate")
+    depends_on("magma+cuda", when="+magma+cuda")
+    depends_on("magma+rocm", when="+magma+rocm")
     depends_on("slate+cuda", when="+cuda+slate")
     depends_on("slate+rocm", when="+rocm+slate")
     for val in ROCmPackage.amdgpu_targets:
@@ -100,6 +103,7 @@ class Strumpack(CMakePackage, CudaPackage, ROCmPackage):
     conflicts("+rocm", when="+cuda")
     conflicts("+slate", when="@:5.1.1")
     conflicts("+slate", when="~mpi")
+    conflicts("+magma", when="~rocm~cuda")
 
     patch("intel-19-compile.patch", when="@3.1.1")
     patch("shared-rocm.patch", when="@5.1.1")
@@ -118,6 +122,7 @@ def cmake_args(self):
             self.define_from_variant("TPL_ENABLE_PARMETIS", "parmetis"),
             self.define_from_variant("TPL_ENABLE_SCOTCH", "scotch"),
             self.define_from_variant("TPL_ENABLE_BPACK", "butterflypack"),
+            self.define_from_variant("TPL_ENABLE_MAGMA", "magma"),
             self.define_from_variant("STRUMPACK_COUNT_FLOPS", "count_flops"),
             self.define_from_variant("STRUMPACK_TASK_TIMERS", "task_timers"),
             "-DTPL_BLAS_LIBRARIES=%s" % spec["blas"].libs.joined(";"),