PR11: Test parsing of library macros.

1. Ensure that 0..5 Ls are OK, but six or seven is an error.

@$@<Sloth_L0@>@Z@{@}
@$@<Sloth_L1@>@Z@L@{@}
@$@<Sloth_L2@>@Z@L@L@{@}
@$@<Sloth_L3@>@Z@L@L@L@{@}
@$@<Sloth_L4@>@Z@L@L@L@L@{@}
@$@<Sloth_L5@>@Z@L@L@L@L@L@{@}
@$@<Sloth_L6@>@Z@L@L@L@L@L@L@{@}
@$@<Sloth_L7@>@Z@L@L@L@L@L@L@L@{@}

2. Ensure that output macros can't also be library macros.

@O@<pr11.out@>@L@{@}

3. Ensure that you cannot define two macros with both the
same name and level. Ensure that this works for all levels.

@$@<Walrus_L0@>@Z@{@}
@$@<Walrus_L0@>@Z@{@}

@$@<Walrus_L1@>@Z@L@{@}
@$@<Walrus_L1@>@Z@L@{@}

@$@<Walrus_L2@>@Z@L@L@{@}
@$@<Walrus_L2@>@Z@L@L@{@}

@$@<Walrus_L3@>@Z@L@L@L@{@}
@$@<Walrus_L3@>@Z@L@L@L@{@}

@$@<Walrus_L4@>@Z@L@L@L@L@{@}
@$@<Walrus_L4@>@Z@L@L@L@L@{@}

@$@<Walrus_L5@>@Z@L@L@L@L@L@{@}
@$@<Walrus_L5@>@Z@L@L@L@L@L@{@}

4. Ensure that six identical levels can simultaneously exist.

@$@<Aardvark_L0@>@Z@{@}
@$@<Aardvark_L1@>@Z@L@{@}
@$@<Aardvark_L2@>@Z@L@L@{@}
@$@<Aardvark_L3@>@Z@L@L@L@{@}
@$@<Aardvark_L4@>@Z@L@L@L@L@{@}
@$@<Aardvark_L5@>@Z@L@L@L@L@L@{@}

5. Ensure that different levels can have different modifiers.

@$@<Emu@>@Z@M@{@}
@$@<Emu@>@Z@L@{@}

6. Ensure that different levels can have different parameter lists.

@$@<Wombat@>@(@3@)@Z@{@}
@$@<Wombat@>@(@1@)@Z@L@{@}

7. Ensure that different levels can have differently additive.

@$@<Penguin@>@Z==@{@}
@$@<Penguin@>@Z@L+=@{@}

End of library construct parser tests.