Re: [Fink-devel] enable path-prefix-clang for SL Xcode 4.2

[Jack H. <ho...@br...>]

On Fri, Oct 21, 2011 at 09:02:56PM +0200, Martin Costabel wrote:
> On 21/10/11 16:04 , Jack Howarth wrote:
>> On Fri, Oct 21, 2011 at 10:06:24AM +0200, Martin Costabel wrote:
>>> On 21/10/11 01:05, Jack Howarth wrote:
>>> []
>>>> should upgrade to this version (or revert to Xcode 3.2.6). This would allow us to
>>>> focus on supporting clang in the Xcode 4.x releases and encourage unification of
>>>> any clang specific changes to info files between the 10.4 and 10.6 trees. It also
>>>> will likely accelerate the elimination of the unstable tree in 10.4 as any clang
>>>> specific changes are backported into 10.4.
>>>
>>> The most common "clang specific changes to info files" are currently
>>> SetCC: llvm-gcc-4.2
>>> SetCXX: llvm-g++
>>> because many packages won't compile with clang.
>>> This is not backportable.
>
>> Martin,
>>     Re-reading your response again, I assume you meant that the info files will never
>> been entirely unified. This is true however that shouldn't stand in our way of attempting
>> to make fink usable for SL users who have Xcode 4.2 installed. We really only have two
>> choices there...
>>
>> 1) Leave fink as is and manually check if each info file is miscompiled by llvm-gcc.
>> This is a lot of work for a smallish testing and developer group to deal with. It also
>> requires far more info file changes to switch these problem packages to clang or gcc-4.2.
>> 2) Use my approach of enabling the path-prefix-clang on SL when Xcode 4.2 is detected via
>> the system compiler change. This gives us a well tested package set which already has been
>> checked against clang3.0svn.
>
> What I mean is that a package that does not compile under clang needs to  
> include the above fix for xcode-4.2 if your automatic switch to clang is  
> implemented. But then it will probably no longer work on 10.5 and on  
> 10.6 with xcode-3.2. You would need one info file for xcode-4.2 and  
> another one for xcode<=3.2. I don't see how this is possible inside the  
> 10.4 tree.

I don't see why this has to be so complex. If you run into package that is incompatible with
clang, just use...

if [ `gcc -v 2>&1 | grep -c clang` = "1" ]; then
export CC=llvm-gcc-4.2
export CXX=llvm-g++-4.2
fi

We could create a path-prefix-gcc42 to force the SL Xcode 4.2 compilers under fink to use
gcc-4.2/g++-4.2 but that doesn't promote the general progress by encouraging testing of
i386 code generation from clang.

>
> -- 
> Martin