cheribsd: Set MAKEOBJDIRPREFIX lazily pre-setup()

We can't just do it eagerly in __init__ since we need _init_called to be
set to true by Target.create_project for cheribsd-mfs-root-kernel (its
builddir will call cheribsd_reuse_build_dir, which then gets the base
cheribsd instance, which asserts that the caller is already
initialised).

This is all a bit of a mess still, as it seems that all the make_args
setting in setup() should be done in _setup_make_args(), with setup()
either calling _setup_make_args() if needed or just letting the laziness
do its job if not, but I don't want to untangle all that.

pycheribuild/projects/cross/cheribsd.py

@@ -525,13 +525,22 @@ def check_system_dependencies(self) -> None:
 
  def __init__(self, *args, **kwargs) -> None:
  super().__init__(*args, **kwargs)
+ self._setup_core_make_args_called = False
+
+ def _setup_core_make_args(self) -> None:
+ if self._setup_core_make_args_called:
+ return
+
  # Needed pre-setup for _query_make_var() (e.g. via objdir)
  self.make_args.set_env(MAKEOBJDIRPREFIX=str(self.build_dir))
  # TODO? Avoid lots of nested child directories by using MAKEOBJDIR instead of MAKEOBJDIRPREFIX
  # self.make_args.set_env(MAKEOBJDIR=str(self.build_dir))
 
+ self._setup_core_make_args_called = True
+
  def setup(self) -> None:
  super().setup()
+ self._setup_core_make_args()
 
  if self.crossbuild:
  # Use the script that I added for building on Linux/MacOS:
@@ -828,6 +837,9 @@ def _setup_make_args(self) -> None:
  # Same as setup() but can be called multiple times.
  if self._setup_make_args_called:
  return
+
+ self._setup_core_make_args()
+
  # Must be called after __init__() to ensure that CHERI LLVM/upstream LLVM have been built
  # before querying the compiler.
  if self.crossbuild: