On 07/02/2012 02:57 PM, Stefano Lattarini wrote: > On 07/02/2012 02:26 PM, Ralf Corsepius wrote: >> On 06/30/2012 08:30 PM, Stefano Lattarini wrote: >>> Maintaining ACLOCAL_AMFLAGS in the Makefile.am to pass extra flags >>> to aclocal is (and have always been) quite of an hack. For example, >>> autoreconf is forced to grep Makefile.am to honour those flags. But >>> this is a bad obsolescent behaviour; in fact, the autotools have moved >>> consistently in the past years from custom grepping of Makefile.am and >>> configure.ac to tracing of m4 macro calls, which is more consistent, >>> more reliable and more flexible. >>> >>> And when autoreconf is not used, the developer is forced to add *by hand* >>> the flags specified by ACLOCAL_AMFLAGS to the aclocal calls not triggered >>> by make rebuild rules; here lie again more duplication and more chances >>> for errors. >>> >>> Moreover, ACLOCAL_AMFLAGS has only two typical use cases: >>> >>> - to instruct aclocal to look for extra macro definition in a local >>> directory (as with "ACLOCAL_AMFLAGS = -I m4"); and >>> >>> - to further instruct aclocal to copy in that local directory the >>> required third-party .m4 files found in the system-wide directory >>> (as with "ACLOCAL_AMFLAGS = -I m4 --install"). >>> >>> The first use case can be better covered if aclocal can instead trace and >>> honours call to the AC_CONFIG_MACRO_DIR autoconf macro; and the second >>> use case shouldn't be considered really legitimate, as it is quite (and >>> subtly) brittle (see automake bug#9037). >> >> ACLOCAL_AMFLAGS is able to take sequences of "-I's". >> >> Will your AC_CONFIG_MACRO_DIR be able handle such cases? >> > No; and I think there is no compelling reason to support multiple local > m4 macro dirs in a build system setup. > > But I recognize I might be proven wrong, so here's a sketch of how I > plan to proceed in this case. > > Once we start warning about ACLOCAL_AMFLAGS (in Automake 1.14), people > that were using multiple '-I' option there will see that the new semantics > don't support their setup anymore. So they'll either adjust such setup, > or, if that turns out to be impossible, will write to bug-automake to > complain. If their complain turns out to be legitimate, we will add a > new autoconf macro 'AM_EXTRA_LOCAL_M4_DIRS' (say), that aclocal will > trace and use to adjust its search path accordingly. > I've now pushed this patch.
Regards, Stefano
