Ghost as cuda package (#7501)

* add headers  property to netlib-lapack and intel-mkl

* ghost: fix finding cblas header and libs (at least for mkl and netlib-lapack, which provide headers())

* fix flake8 errors

* ghost: remove unnecessary query parameter

* fix flake8 errors

* ghost: make it a CudaPackage (as suggested by @davydden, thanks!)

* ghost: missing whitespace

var/spack/repos/builtin/packages/intel-mkl/package.py

@@ -182,6 +182,18 @@ def scalapack_libs(self):
 
         return libs
 
+    @property
+    def headers(self):
+        prefix = self.spec.prefix
+        if sys.platform != 'darwin':
+            include_dir = prefix.compilers_and_libraries.linux.mkl.include
+        else:
+            include_dir = prefix.include
+
+        cblas_h = join_path(include_dir, 'mkl_cblas.h')
+        lapacke_h = join_path(include_dir, 'mkl_lapacke.h')
+        return HeaderList([cblas_h, lapacke_h])
+
     def setup_dependent_environment(self, spack_env, run_env, dependent_spec):
         # set up MKLROOT for everyone using MKL package
         if sys.platform == 'darwin':