4.10 Configuring Other Packages in Subdirectories

In most situations, calling AC_OUTPUT is sufficient to produce `Makefile's in subdirectories. However, configure scripts that control more than one independent package can use AC_CONFIG_SUBDIRS to run configure scripts for other packages in subdirectories.

Macro: AC_CONFIG_SUBDIRS (dir ...)

Make AC_OUTPUT run configure in each subdirectory dir in the given whitespace-separated list. Each dir should be a literal, i.e., please do not use:

if test "$package_foo_enabled" = yes; then $my_subdirs="$my_subdirs foo" fi AC_CONFIG_SUBDIRS($my_subdirs)

because this prevents `./configure --help=recursive' from displaying the options of the package foo. Rather, you should write:

if test "$package_foo_enabled" = yes then; AC_CONFIG_SUBDIRS(foo) fi

If a given dir is not found, no error is reported, so a configure script can configure whichever parts of a large source tree are present. If a given dir contains configure.gnu, it is run instead of configure. This is for packages that might use a non-autoconf script Configure, which can't be called through a wrapper configure since it would be the same file on case-insensitive filesystems. Likewise, if a dir contains `configure.ac' but no configure, the Cygnus configure script found by AC_CONFIG_AUX_DIR is used.

The subdirectory configure scripts are given the same command line options that were given to this configure script, with minor changes if needed (e.g., to adjust a relative path for the cache file or source directory). This macro also sets the output variable subdirs to the list of directories `dir ...'. `Makefile' rules can use this variable to determine which subdirectories to recurse into. This macro may be called multiple times.