CMakePackage: convert variants to CMake arguments (#14376)

Add a 'define_from_variant` helper function to CMake-based Spack
packages to convert package variants into CMake arguments. For
example:

  args.append('-DFOO=%s' % ('ON' if '+foo' in self.spec else 'OFF'))

can be replaced with:

  args.append(self.define_from_variant('foo'))

The following conversions are handled automatically:

* Flag variants will be converted to CMake booleans
* Multivalued variants will be converted to semicolon-separated strings
* Other variant values are converted to CMake string arguments

This also adds a 'define' helper method to convert any variable to
a CMake argument. It has the same conversion rules as
'define_from_variant' (but operates directly on values rather than
requiring the user to supply the name of a package variant).

0 files changed, 0 insertions, 0 deletions