Re: [PATCH] configure: test shell parameter substring processing and possibly exec one

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+From: David Bremner <david@tethera.net>\r
+To: Tomi Ollila <tomi.ollila@iki.fi>, notmuch@notmuchmail.org\r
+Subject: Re: [PATCH] configure: test shell parameter substring processing and\r
+       possibly exec one\r
+In-Reply-To: <1334643263-30207-1-git-send-email-tomi.ollila@iki.fi>\r
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+Date: Wed, 02 May 2012 19:25:53 -0300\r
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+\r
+\r
+\r
+I'm still a bit leery of over-complicating the configure script to\r
+support legacy /bin/sh; however, I guess I'm at least convinced that the\r
+only trivial solution is just to document the requirement for posix\r
+/bin/sh.  It will be odd to back this out and document the restriction\r
+later, so please chime in now if you have strong feelings either way.\r
+\r
+Tomi Ollila <tomi.ollila@iki.fi> writes:\r
+\r
+> To tackle this situation the beginning of configure attemts to do a silent\r
+> parameter substitution in a subshell; in case this fails the subshell exits\r
+> with nonzero value which is easy to detect.\r
+\r
+s/attemts/attempts/\r
+\r
+> The || constructs are used twice. The first one is used as Bourne shell\r
+> chokes on 'if ! ... ' construct (and if ...; then :; else do_things; fi\r
+> looks stupid). The second one(liner) takes care of the possible future\r
+> addition of 'set -eu' in the beginning of this script.\r
+\r
+OK, although I might have gone for the empty if myself.\r
+\r
+> +# If not, attempt to locate and launch one which probably can.\r
+\r
+> +( option=option=value; : ${option#*=} ) 2>/dev/null || {\r
+\r
+option=option=value seems a little _too_ clever to me. Any reason not to\r
+use e.g. \r
+\r
+option="A,B" \r
+\r
+> +    if test x"${_NOTMUCH_CONFIGURE-}" = x ; then\r
+> +    _NOTMUCH_CONFIGURE=1; export _NOTMUCH_CONFIGURE\r
+\r
+This could probably use a comment.\r
+\r
+> +    for x in /bin/ksh /bin/bash /usr/bin/bash\r
+\r
+I guess add /usr/local/bin/bash?  I'm slightly worried this list will\r
+just keep growing.\r