cln uses cmake as build_system starting from 1.3

use multibuid system

cln: switch to cmake build_system and fix 1.3.7 build #8

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

@@ -43,7 +43,7 @@ class Cln(CMakePackage, AutotoolsPackage):
 
     # Build system
     build_system(
-        conditional("cmake", when="@1.4:"), conditional("autotools", when="@:1.3"), default="cmake"
+        conditional("cmake", when="@1.3:"), conditional("autotools", when="@:1.2.2"), default="cmake"
     )
 
     with when("build_system=autotools"):