Add spack edit option for build systems (#2865)

lib/spack/spack/__init__.py

@@ -46,6 +46,7 @@
 module_path    = join_path(lib_path, "spack")
 platform_path  = join_path(module_path, 'platforms')
 compilers_path = join_path(module_path, "compilers")
+build_systems_path = join_path(module_path, 'build_systems')
 operating_system_path = join_path(module_path, 'operating_systems')
 test_path      = join_path(module_path, "test")
 hooks_path     = join_path(module_path, "hooks")

lib/spack/spack/cmd/edit.py

@@ -69,6 +69,10 @@ def setup_parser(subparser):
 
     # Various types of Spack files that can be edited
     # Edits package files by default
+    excl_args.add_argument(
+        '-b', '--build-system', dest='path', action='store_const',
+        const=spack.build_systems_path,
+        help="Edit the build system with the supplied name.")
     excl_args.add_argument(
         '-c', '--command', dest='path', action='store_const',
         const=spack.cmd.command_path,