automake-1.16: Nested Packages

 
 2.2.13 Nested Packages
 ----------------------
 
 Although nesting packages isn’t something we would recommend to someone
 who is discovering the Autotools, it is a nice feature worthy of mention
 in this small advertising tour.
 
    Autoconfiscated packages (that means packages whose build system have
 been created by Autoconf and friends) can be nested to arbitrary depth.
 
    A typical setup is that package A will distribute one of the
 libraries it needs in a subdirectory.  This library B is a complete
 package with its own GNU Build System.  The ‘configure’ script of A will
 run the ‘configure’ script of B as part of its execution; building and
 installing A will also build and install B. Generating a distribution
 for A will also include B.
 
    It is possible to gather several packages like this.  GCC is a heavy
 user of this feature.  This gives installers a single package to
 configure, build and install, while it allows developers to work on
 subpackages independently.
 
    When configuring nested packages, the ‘configure’ options given to
 the top-level ‘configure’ are passed recursively to nested ‘configure’s.
 A package that does not understand an option will ignore it, assuming it
 is meaningful to some other package.
 
    The command ‘configure --help=recursive’ can be used to display the
 options supported by all the included packages.
 
    ⇒Subpackages, for an example setup.