Add universal build_type variant to CMakePackage (#4797)

* Add universal build_type variant to CMakePackage
* Override build_type in some packages with different possible values
* Remove reference to no longer existent debug variant
* Update CBTF packages with new build_type variant
* Keep note on build size of LLVM

var/spack/repos/builtin/packages/clamr/package.py

@@ -41,10 +41,6 @@ class Clamr(CMakePackage):
         'graphics', default='opengl',
         values=('opengl', 'mpe', 'none'),
         description='Build with specified graphics support')
-    variant(
-        'build', default='relwithdebinfo',
-        values=('debug', 'release', 'relwithdebinfo'),
-        description='Build type')
     variant(
         'precision', default='mixed',
         values=('single', 'mixed', 'full'),
@@ -53,15 +49,6 @@ class Clamr(CMakePackage):
     depends_on('mpi')
     depends_on('mpe', when='graphics=mpe')
 
-    def build_type(self):
-        spec = self.spec
-        if 'build=debug' in spec:
-            return 'Debug'
-        elif 'build=release' in spec:
-            return 'Release'
-        else:
-            return 'RelWithDebInfo'
-
     def cmake_args(self):
         spec = self.spec
         cmake_args = []