Autoconf changes, and throughout the years some constructs are obsoleted. Most of the changes involve the macros, but the tools themselves, or even some concepts, are now considered obsolete.
You may completely skip this chapter if you are new to Autoconf, its intention is mainly to help maintainers updating their packages by understanding how to move to more modern constructs.
config.status now supports arguments to specify the files to instantiate, see Chapter 15, for more details. Before, environment variables had to be used.
function>CONFIG_COMMANDS/function> The tags of the commands to execute. The default is the arguments given to AC_OUTPUT and AC_CONFIG_COMMANDS in configure.ac.
function>CONFIG_FILES/function> The files in which to perform @variable@ substitutions. The default is the arguments given to AC_OUTPUT and AC_CONFIG_FILES in configure.ac.
function>CONFIG_HEADERS/function> The files in which to substitute C #define statements. The default is the arguments given to AC_CONFIG_HEADERS; if that macro was not called, config.status ignores this variable.
function>CONFIG_LINKS/function> The symbolic links to establish. The default is the arguments given to AC_CONFIG_LINKS; if that macro was not called, config.status ignores this variable.
In Chapter 15, using this old interface, the example would be:
config.h: stamp-h stamp-h: config.h.in config.status CONFIG_COMMANDS= CONFIG_LINKS= CONFIG_FILES= \ CONFIG_HEADERS=config.h ./config.status echo stamp-h Makefile: Makefile.in config.status CONFIG_COMMANDS= CONFIG_LINKS= CONFIG_HEADERS= \ CONFIG_FILES=Makefile ./config.status
(If configure.ac does not call AC_CONFIG_HEADERS, there is no need to set CONFIG_HEADERS in the make rules, equally for CONFIG_COMMANDS etc.)