27.2.2 AM_MAINTAINER_MODE

AM_MAINTAINER_MODE disables the so called "rebuild rules" by default. If you have AM_MAINTAINER_MODE in ‘configure.ac’, and run ‘./configure && make’, then make will *never* attempt to rebuilt ‘configure’, ‘Makefile.in’s, Lex or Yacc outputs, etc. I.e., this disables build rules for files that are usually distributed and that users should normally not have to update.

If you run ‘./configure --enable-maintainer-mode’, then these rebuild rules will be active.

People use AM_MAINTAINER_MODE either because they do want their users (or themselves) annoyed by timestamps lossage (see section CVS and generated files), or because they simply can't stand the rebuild rules and prefer running maintainer tools explicitly.

AM_MAINTAINER_MODE also allows you to disable some custom build rules conditionally. Some developers use this feature to disable rules that need exotic tools that users may not have available.

Several years ago François Pinard pointed out several arguments against this AM_MAINTAINER_MODE macro. Most of them relate to insecurity. By removing dependencies you get non-dependable builds: change to sources files can have no effect on generated files and this can be very confusing when unnoticed. He adds that security shouldn't be reserved to maintainers (what ‘--enable-maintainer-mode’ suggests), on the contrary. If one user has to modify a ‘Makefile.am’, then either ‘Makefile.in’ should be updated or a warning should be output (this is what Automake uses missing for) but the last thing you want is that nothing happens and the user doesn't notice it (this is what happens when rebuild rules are disabled by AM_MAINTAINER_MODE).

Jim Meyering, the inventor of the AM_MAINTAINER_MODE macro was swayed by François's arguments, and got rid of AM_MAINTAINER_MODE in all of his packages.

Still many people continue to use AM_MAINTAINER_MODE, because it helps them working on projects where all files are kept under CVS, and because missing isn't enough if you have the wrong version of the tools.