[ng] general: simpler workaround for CDPATH issues

With this change, we also get rid of the $(am__cd) make variable.

* lib/am/header-vars.am (am__cd): Remove.
To ensure a CDPATH exported in the environment doesn't interfere with
our scripts and recipes, we can simply un-export it here (using the GNU
make "unexport" directive), rather than having to rely on $(am__cd) ...
* Makefile.am, automake.in, lib/am/configure.am, lib/am/distdir.am,
lib/am/header-vars.am, lib/am/inst-vars.am, lib/am/remake-hdr.am,
lib/am/tags.am, lib/am/texibuild.am, t/ax/distcheck-hook-m4.am: ... in
several places of these files.
* GNUmakefile, HACKING: Adjust.
* syntax-checks.mk (sc_cd_in_backquotes, sc_cd_relative_dir): Remove,
superseded by ...
(sc_no_am_cd): ... this new target, which has contrary semantics, and
looks *against* the use of the now-obsolete $(am__cd).
(syntax_check_rules): Adjust.

Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>

1 files changed, 0 insertions, 6 deletions

diff --git a/HACKING b/HACKING
index 696638447..c15718f55 100644
--- a/HACKING
+++ b/HACKING
@@ -64,12 +64,6 @@
 
 * Never use basename or dirname.  Instead use sed.
 
-* Do not use 'cd' within back-quotes, use '$(am__cd)' instead.
-  Otherwise the directory name may be printed, depending on CDPATH.
-  More generally, do not ever use plain 'cd' together with a relative
-  directory that does not start with a dot, or you might end up in one
-  computed with CDPATH.
-
 * For install and uninstall rules, if a loop is required, it should be
   silent.  Then the body of the loop itself should print each
   "important" command it runs.  The printed commands should be preceded