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/gmsh/package.py

@@ -46,8 +46,6 @@ class Gmsh(CMakePackage):
 
     variant('shared',      default=True,
             description='Enables the build of shared libraries')
-    variant('debug',       default=False,
-            description='Builds the library in debug mode')
     variant('mpi',         default=True,
             description='Builds MPI support for parser and solver')
     variant('fltk',        default=False,
@@ -128,9 +126,6 @@ def cmake_args(self):
             # Builds and installs static library
             options.append('-DENABLE_BUILD_LIB:BOOL=ON')
 
-        if '+debug' in spec:
-            options.append('-DCMAKE_BUILD_TYPE:STRING=Debug')
-
         if '+mpi' in spec:
             options.append('-DENABLE_MPI:BOOL=ON')