Re: Compiling under Ubuntu 16.04

[David Chisnall]

> On 26 Aug 2016, at 14:28, Matthew Butch <apple4ever@me.com> wrote:
> 
> Thanks for the comments! Mine are below:
> 
> 
>> On Aug 26, 2016, at 04:46, David Chisnall <theraven@sucs.org> wrote:
>> 
>> Please will you remove the first build of GNUstep Make.  Neither libdispatch 
>> nor libobjc2 need GNUstep Make (in the case of libobjc2, intentionally to 
>> avoid a circular dependency).
>> 
>> If -Make is not installed, then libobjc2 will install as a normal library, 
>> just set the prefix to whatever you want (it defaults to /usr/local, you 
>> probably want /usr on Ubuntu).
> 
> I did see a previous post on the list here about that. But I could not get it 
> to work. I could not get further builds of GNUstep to properly build and use 
> either /usr or /usr/local when libobjc2 was installed there. 
> 
> If you have any suggestions as to the correct flags to get it to work, I’d be 
> happy to try again. 

I’m not sure of any special flags that are needed.  On FreeBSD, we ship 
packages of libobjc2 that don’t depend on any other bits of GNUstep to build, 
install in /usr/local, and are picked up automatically by GNUstep Make with no 
other issues.  What errors do you see?

>> Ubuntu 16.04 includes clang 3.8 (clang-3.8 package), which is ample for 
>> compiling modern Objective-C code (and, for the next couple of weeks, is the 
>> latest release), so it’s probably more sensible to install that than to 
>> build from source.  Even better, they’ve now fixed the idiocy from Ubuntu 
>> 14.04 where you then had to force-deinstall a bunch of gcc packages that 
>> they made the clang package depend on to get a working compiler.
> 
> Which I do. Maybe you were looking at the 14.04 & 15.04 scripts which I 
> didn’t change? 

Ooops!  I didn’t scroll back up as far as I thought I’d done.

> 
>> You will need to update the [OBJ]C[XX]FLAGS everywhere because now clang / 
>> clang++ are called clang-3.8 and clang++-3.8.
> 
> Do I? Everything seemed to work fine with the repository installed version 
> without doing that. 

Ah, I didn’t realise there was also a clang package that installs sensible 
symlinks.  Ignore me.

> 
>> I don’t know why you think you need '-DCMAKE_ASM_FLAGS=-c’ in the libobjc2 
>> build.  I just tried cmake -G Ninja -DCMAKE_C_COMPILER=clang-3.8 
>> -DCMAKE_CXX_COMPILER=clang++-3.8 on Ubuntu 16.04 and it seemed to work.
>> It’s also probably not a good idea to pass -DTESTS=OFF - it only takes a few 
>> extra seconds on a moderately modern machine to build and run the tests and 
>> you get a bit of sanity checking early on from doing so.
> 
> That was the recommendation from the INSTALL for libobjc2 
> (https://github.com/gnustep/libobjc2/blob/master/INSTALL#L40)
> 
> If you think they aren’t needed, I can try with out them. 

This was a work-around for a cmake bug, which appears to now be fixed.

> 
>> Please don’t use -fobjc-nonfragile-abi, it’s been deprecated for years.  The 
>> correct flag is -fobjc-runtime=gnustep-1.8.
> 
> Interesting. I didn’t see that anywhere. Will have to update this page to 
> note:
> 
> http://wiki.gnustep.org/index.php/ObjC2_FAQ
> 
> I will correct it. 

This page is far less horribly out of date than it used to be, but it’s still a 
bit in need of love.

> 
>> In theory, the libdispatch0 package from Ubuntu ought to work, though I’ve 
>> not tested it
> 
> I believe I tested it and it didn’t work. But right now I can’t recall what I 
> ran into.
> 
>> This line:
>> 
>> source ~/.bashrc
>> 
>> Is probably dangerous.  You’re already sourcing GNUstep.sh earlier and you 
>> may end up with something very confusing, as many people have .bashrc 
>> scripts that don’t expect to be sourced more than once in a shell.  
>> Similarly, the advice at the end is bad and you should tell people to source 
>> GNUstep.[c]sh, not re-source their .bashrc into a shell that’s already 
>> loaded it (or into a shell that may not understand it if bash is not their 
>> current shell).
> 
> Hmm good point. I added that line because for some reason building the apps 
> would give me errors without it. It grabbed the idea from the old script, and 
> it did work for me- but it was a fresh install. And I originally tried 
> without that advice at the end, but I still got errors trying to build test 
> apps. Maybe better advice would be to close and re-open the terminal.

If you’re installing GNUstep-Make twice, then you might accidentally pick up 
settings from the old one, which is part of the reason for not doing this.

> 
>> The script would be a lot more readable if this were in a function, not 
>> copied and pasted a dozen times:
>> 
>> if [ "$PROMPT" = true ] ; then
>>  echo -e "\n\n"
>>  read -p "${GREEN}Press enter to continue...${NC}”
>> fi
> 
> I agree- I thought about it before I uploaded it. But I wanted to get it out 
> for critiquing and figured I’d change it when I’d make other changes. 

Thanks for doing this,

David