bug#9249: Does Libtool 2.4 support Solaris 2.8?

[Gary V. Vaughan]

Hi Andreas,

On 9 Aug 2011, at 03:31, Andreas Kupries wrote:
> On 8/8/2011 1:09 PM, Gary V. Vaughan wrote:
>> On 9 Aug 2011, at 02:50, Andreas Kupries wrote:
>>> On 8/5/2011 8:18 PM, Gary V. Vaughan wrote:
>>> bash ../../src/configure 
>>> --prefix=/export/home/andreask/dbn/BuildTmp/Hwloc/solaris2.8-sparc/install 
>>> --exec-prefix=/export/home/andreask/dbn/BuildTmp/Hwloc/solaris2.8-sparc/install
>>>  
>>> --with-tcl=/export/home/andreask/dbn/BuildTmp/Hwloc/solaris2.8-sparc/install/lib
>>>  
>>> --with-tk=/export/home/andreask/dbn/BuildTmp/Hwloc/solaris2.8-sparc/install/lib
>>>  --enable-shared --enable-threads
>>> [[...]]
>>> The generated Makefile and libtool however have SHELL=/bin/sh
>>> assignments in them, and without me forcing them to use bash they [[fail]].
>> 
>> Ah, I see the problem.
>> 
>> You needn't tell Autotools that you have a preferred shell
> 
> Wel, I was not reall aware of telling it about a prefered shell, just 
> executing configure via bash.
> 
> Actually, I am kind of surpised that it is apparently possible to run 
> configure with a shell A, under which tests are run, and then having it 
> generate files for a shell B it considers preferable, but was not tested 
> against.

What happens here is that you're effectively going behind configure's back when 
you use '/path/to/some/shell ./configure...', because there is no way for it 
know that it isn't simple running inside the default shell.

> > to the one it looks for by itself (and actually, if you just let configure 
> > run with whatever shell it can get,
> > it might even find and choose /usr/local/bin/bash provided that you have 
> > /usr/local/bin in your command search
> > PATH, and provided that there is not a shell called 'sh' also somewhere in 
> > PATH that provides all the features
> > Autotools is looking for.
> 
> So, is 'configure' re-exec'uting itself with a different shell, if it finds 
> whatever it prefers ?

Yes, exactly that, unless the shell it happens to be inside already works 
satisfactorily.

>> However, you can safely force an alternative shell to execute the various 
>> Autotools scripts by setting both SHELL and CONFIG_SHELL, like so:
>> 
>>    ./configure SHELL=/usr/local/bin/bash 
>> CONFIG_SHELL=/usr/local/bin/bash<other arguments as usual>
> 
> Is it possible to set this through the environment as well ? (It might be 
> easier for the build setup here to put this into the environment of 
> ./configure when it is run. Have to re-check).

No, because ./configure needs to know that you want to generate a Makefile that 
executes libtool with a particular non-discovered shell.  Much the same as you 
need to override internal Makefile variables explicitly with 'make SED=gsed', 
you also need to inform configure that you want to override its shell search 
and re-exec with 'configure SHELL=/path/to/bash CONFIG_SHELL=/path/to/bash', so 
that it can pass that knowledge through to the rest of the build.

Actually, configure and libtool are both written extremely carefully to work 
well with a very basic shell, so you're not buying yourself anything but a 
longer wait by forcing the use of bash.  It's all well and good that you want 
to write and execute your own scripts in Bash, but I don't see the advantage in 
forcing Autotools to use the much slower bash when the developers of Autotools 
have gone to great lengths to dynamically select the best available shell to 
execute themselves quickly and correctly.

> I should note that SHELL is set in the global environment too, to 
> 'path/to/bash'.
> Its apparently only CONFIG_SHELL I might have to set.

Yes, that's right.

>> That should ensure that SHELL is then set correctly in libtool and Makefile 
>> to match the tests that configure ran earlier.
> 
> Thanks for all the help.

You're welcome.

Cheers,
-- 
Gary V. Vaughan (gary AT gnu DOT org)