5.9.2 Qualified Projects
Before the reserved project, there may be one or two `qualifiers', that
is identifiers or reserved words, to qualify the project.
The current list of qualifiers is:
Qualifies a project with no sources.
Such a project must either have no declaration of attributes Source_Dirs,
Source_Files, Languages or Source_List_File, or one of
Source_Dirs, Source_Files, or Languages must be declared
as empty. If it extends another project, the project it extends must also be a
qualified abstract project.
A standard project is a non library project with sources.
This is the default (implicit) qualifier.
A project whose sources are aggregated from other project files.
- `aggregate library':
A library whose sources are aggregated from other project
or library project files.
A library project must declare both attributes
Library_Name` and Library_Dir.
A configuration project cannot be in a project tree.
It describes compilers and other tools to `gprbuild'.