[!23] Respect the build type variant added by the CMakePackage class

Merge branch 'feature/respect-build-type-variant' into 'master'

ref:spack/dune-spack\> Fixes [#16]

See merge request [spack/dune-spack!23]

  [#16]: gitlab.dune-project.org/NoneNone/issues/16
  [spack/dune-spack!23]: gitlab.dune-project.org/spack/dune-spack/merge_requests/23


Closes #16

packages/dune/package.py

@@ -342,6 +342,7 @@ class Dune(CMakePackage):
             return variant_bool(feature, on='OFF', off='ON')
 
         cmake_args = [ 
+            '-DCMAKE_BUILD_TYPE:STRING=%s' % self.spec.variants['build_type'].value,
             '-DBUILD_SHARED_LIBS:BOOL=%s' % variant_bool('+shared'),
             '-DDUNE_GRID_GRIDTYPE_SELECTOR:BOOL=ON',
             '-DCMAKE_DISABLE_FIND_PACKAGE_Doxygen:BOOL=%s' % nvariant_bool('+doc'),