Re: aclocal 1.8 no longer loads overridden macros

[Alexandre Duret-Lutz]

>>> "Andreas" == Andreas Schwab <address@hidden> writes:

 Andreas> Alexandre Duret-Lutz <address@hidden> writes:
 >>>>> "Andreas" == Andreas Schwab <address@hidden> writes:
 >> 
 Andreas> With aclocal 1.8 you no longer get overridden standard
 Andreas> autoconf macros loaded from local *.m4 files.
 >> 
 >> I could not reproduce this (tried to redefine AC_PROG_CC
 >> successfully).  Can you send detailed instructions?

[...]

 Andreas> running "aclocal -I m4" in the coreutils-5.0 source
 Andreas> directory does not include the file m4/search-libs.m4
 Andreas> in aclocal.m4.

CC'ed Jim for this. 

[...]

 Andreas> Here is a testcase:

 Andreas> $ cat configure.ac
 Andreas> AC_INIT([aclocal-test], [0])
 Andreas> AC_PROG_CC
 Andreas> AC_OUTPUT
 Andreas> $ cat prog-cc.m4
 Andreas> undefine([AC_PROG_CC])
 Andreas> AC_DEFUN([AC_PROG_CC], [echo [AC_PROG_CC] dummy])
 Andreas> $ aclocal -I .
 Andreas> $ cat aclocal.m4
 Andreas> cat: aclocal.m4: No such file or directory

 Andreas> The problem is caused by the call to undefine, this
 Andreas> loses the traced attribute.

Thanks for investigating this.  

I think we can't do anything about this in aclocal, apart from
documenting this new incompatibility.  Since we are obviously
relying on --trace more and more, maybe we should prohibit all
macros that can affect the trace attribute.  Is undefine() the
sole such macro, or are there others?

Are there cases where undefine() is needed?  It seems
superfluous in m4/search-libs.m4.
-- 
Alexandre Duret-Lutz