GNU bug report logs - #35526
misleading documentation about flag variable ordering

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From: Daniel Kahn Gillmor <dkg <at> fifthhorseman.net>
To: 35526 <at> debbugs.gnu.org
Subject: bug#35526: misleading documentation about flag variable ordering
Date: Wed, 01 May 2019 13:33:16 -0400

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https://www.gnu.org/software/automake/manual/automake.html#Flag-Variables-Ordering

says:

    The reason ‘$(CPPFLAGS)’ appears after ‘$(AM_CPPFLAGS)’ or
    ‘$(mumble_CPPFLAGS)’ in the compile command is that users should
    always have the last say.

The implication here is that for any of the *FLAGS variables, later
options are inherently more effective than earlier options.

This is not the case universally.  For example -Wl,--as-needed is more
effective if it shows up earlier in the command line.  (see
https://bugs.debian.org/347650 for a libtool-related problem for that
kind of ordering/re-ordering)

It would be good if the documentation could avoid implying something
that isn't the case, because that dubious suggestion casts doubt on the
rest of the documentation (or on the user's understanding of the rest of
the buildsystem)

thanks for maintaining automake!

    --dkg

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