Intel prefixes (#7469)

Consolidate prefix calculation logic for intel packages into the
IntelPackage class.

Add documentation on installing Intel packages with Spack an
(alternatively) adding them as external packages in Spack.

lib/spack/docs/basic_usage.rst

@@ -596,6 +596,9 @@ name or compiler specifier to their left in the spec.
 If the compiler spec is omitted, Spack will choose a default compiler
 based on site policies.
 
+
+.. _basic-variants:
+
 ^^^^^^^^
 Variants
 ^^^^^^^^

lib/spack/docs/getting_started.rst

@@ -484,6 +484,9 @@ simple package.  For example:
 
    $ spack install zlib%gcc@5.3.0
 
+
+.. _vendor-specific-compiler-configuration:
+
 --------------------------------------
 Vendor-Specific Compiler Configuration
 --------------------------------------

lib/spack/docs/module_file_support.rst

@@ -479,6 +479,9 @@ you will prevent the generation of module files for any package that
 is compiled with ``gcc@4.4.7``, with the only exception of any ``gcc``
 or any ``llvm`` installation.
 
+
+.. _modules-naming-scheme:
+
 """""""""""""""""""""""""""
 Customize the naming scheme
 """""""""""""""""""""""""""

lib/spack/docs/packaging_guide.rst

@@ -2759,6 +2759,8 @@ is handy when a package supports additional variants like
 
    variant('openmp', default=True, description="Enable OpenMP support.")
 
+.. _blas_lapack_scalapack:
+
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 Blas, Lapack and ScaLapack libraries
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

lib/spack/docs/tutorial_configuration.rst

@@ -325,6 +325,8 @@ license server, you can set this in ``compilers.yaml`` as follows:
       ...
 
 
+.. _configs-tutorial-package-prefs:
+
 -------------------------------
 Configuring Package Preferences
 -------------------------------