kokkos: add pic option (#9643)

Since kokkos only compiles a static library, the -fPIC compiler flag
is required to link kokkos into a Fortran executable

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

@@ -31,6 +31,10 @@ class Kokkos(Package):
     variant('cuda', default=False, description="enable Cuda backend")
     variant('openmp', default=False, description="enable OpenMP backend")
 
+    # Compilation options
+    variant('pic', default=False,
+            description="enable position independent code (-fPIC flag)")
+
     # Kokkos options
     variant('aggressive_vectorization', default=False,
             description="set aggressive_vectorization Kokkos option")
@@ -138,6 +142,10 @@ def install(self, spec, prefix):
             kokkos_options_args = []
             cuda_options_args = []
 
+            # PIC
+            if '+pic' in spec:
+                g_args.append('--cxxflags=-fPIC')
+
             # Backends
             if '+serial' in spec:
                 g_args.append('--with-serial')