** Help for users of RULES=autoconf **

These rules can be used by build items that require some
autoconf-based configuration either internally for to provide
information for their users.

Note: there have been some problems reported with autoconf rules in
parallel builds (with --make-jobs).  It is recommended that you place

attributes: serial

in the Abuild.conf of build items that use autoconf rules.

In order for these rules to work, the following conventions must be
followed:

 - The configure input file must be called configure.ac

 - If the AUTOCONFIGH variable is defined, configure.ac must include
   the statement AC_CONFIG_HEADERS([header.h]) where header.h is the
   value of the AUTOCONFIGH.  The header file must be named in such a
   way as to avoid naming clashes with those created by other build
   items.

 - Any custom m4 macros used by the configure.ac script are in a
   directory called m4 and end with the extension .m4

The following variables may be defined in Abuild.mk:

  AUTOFILES: must be set to the list of files that appear in
      AC_CONFIG_FILES in configure.ac

  AUTOCONFIGH: must be set to the name of the header file in
      AC_CONFIG_HEADERS in configure.ac

Additionally, the following variable may be set if needed:

  CONFIGURE_ARGS: additional arguments to be passed to ./configure


** Help for Abuild.interface for autoconf build items **

Generally, Abuild.interface files for autoconf-based build items will
assign to INCLUDES for the benefit of any C/C++ build items that use
this.  See help for the ccxx rule set for details.  It is also common
for autoconf-based build items to generate an autoconf.interface file
to be declared in Abuild.interface as an autofile.  This allows
additinal variables to be set based on the output of autoconf.