aclocal's -I option

[Bruno Haible]

Hi,

Many .m4 files evolve over time. It therefore often happens that a
package must ship with a .m4 file that is newer than the one installed
in /usr/share/aclocal/. For example, many users still have gettext.m4
from gettext-0.10.35 installed in /usr/share/aclocal/ but when
gettext's configure.in is touched I want 'aclocal' to take the
included gettext-0.10.38/m4/gettext.m4. Same thing for libtool.m4.
Currently aclocal from automake-1.4 gives "duplicated macro" errors
for all macros that are both in /usr/share/aclocal/ and in the
directory indicated by the -I option.

To reproduce:

- Take gettext-0.10.38,

- Run "aclocal -I m4"

It complains:

aclocal: m4/libtool.m4: 25: duplicated macro `AC_PROG_LIBTOOL'
aclocal: m4/libtool.m4: 55: duplicated macro `AC_LIBTOOL_SETUP'
aclocal: m4/libtool.m4: 135: duplicated macro `AC_LIBTOOL_DLOPEN'
aclocal: m4/libtool.m4: 138: duplicated macro `AC_LIBTOOL_WIN32_DLL'
aclocal: m4/libtool.m4: 144: duplicated macro `AC_ENABLE_SHARED'
aclocal: m4/libtool.m4: 170: duplicated macro `AC_DISABLE_SHARED'
aclocal: m4/libtool.m4: 177: duplicated macro `AC_ENABLE_STATIC'
aclocal: m4/libtool.m4: 203: duplicated macro `AC_DISABLE_STATIC'
aclocal: m4/libtool.m4: 211: duplicated macro `AC_ENABLE_FAST_INSTALL'
aclocal: m4/libtool.m4: 237: duplicated macro `AC_DISABLE_FAST_INSTALL'
aclocal: m4/libtool.m4: 241: duplicated macro `AC_PROG_LD'
aclocal: m4/libtool.m4: 311: duplicated macro `AC_PROG_LD_GNU'
aclocal: m4/libtool.m4: 322: duplicated macro `AC_PROG_NM'
aclocal: m4/libtool.m4: 356: duplicated macro `AC_CHECK_LIBM'
aclocal: m4/libtool.m4: 383: duplicated macro `AC_LIBLTDL_CONVENIENCE'
aclocal: m4/libtool.m4: 404: duplicated macro `AC_LIBLTDL_INSTALLABLE'
aclocal: m4/libtool.m4: 425: duplicated macro `AM_PROG_LIBTOOL'
aclocal: m4/libtool.m4: 426: duplicated macro `AM_ENABLE_SHARED'
aclocal: m4/libtool.m4: 427: duplicated macro `AM_ENABLE_STATIC'
aclocal: m4/libtool.m4: 428: duplicated macro `AM_DISABLE_SHARED'
aclocal: m4/libtool.m4: 429: duplicated macro `AM_DISABLE_STATIC'
aclocal: m4/libtool.m4: 430: duplicated macro `AM_PROG_LD'
aclocal: m4/libtool.m4: 431: duplicated macro `AM_PROG_NM'

Suggestion:

Change the semantics of the -I option in such a way that .m4 files
which exist in the -I directory and in /usr/share/aclocal/ are taken
*only* from the -I directory. (Based on the file name, not on the
macro name. It is rare to define macros with the same name in
differently named files.)

To work around this problem, I've had to make a wrapper script
'aclocal.sh' around 'aclocal', but it is a hack.

Bruno