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  • Dylan Baker's avatar
    meson: fix warnings about comparing unlike types · b5f92b6f
    Dylan Baker authored
    
    
    In the old days (0.42.x), when mesa's meson system was written the
    recommendation for handling conditional dependencies was to define them
    as empty lists. When meson would evaluate the dependencies of a target
    it would recursively flatten all of the arguments, and empty lists would
    be removed. There are some problems with this, among them that lists and
    dependencies have different methods (namely .found()), so the
    recommendation changed to use `dependency('', required : false)` for
    such cases.  This has the advantage of providing a .found() method, so
    there is no need to do things like `dep_foo != [] and dep_foo.found()`,
    such a dependency should never exist.
    
    I've tested this with 0.42 (the minimum we claim to support) and 0.45.
    On 0.45 this removes warnings about comparing unlike types, such as:
    
    meson.build:1337: WARNING: Trying to compare values of different types
    (DependencyHolder, list) using !=.
    
    v2: - Use dependency('', required : false) instead of
          declare_dependency(), the later will always report that it is
          found, which is not what we want.
    
    Signed-off-by: default avatarDylan Baker <dylan.c.baker@intel.com>
    Reviewed-by: default avatarCaio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
    b5f92b6f