On Jan 31, 2022, at 13:18, Julien Salort wrote:
> Le 31/01/2022 à 12:08, Ryan Schmidt a écrit :
>
>> The situation is:
>>
>> libgfortran.5.dylib was built with an install_name containing @rpath. (It
>> was the choice of the developers of libgfortran (the developers of gcc), or
>> possibly whoever updates the gcc-devel portfile, to make it do that.)
>>
>> This means that any consumer of that library needs to specify what path(s)
>> @rpath should expand to at runtime, by using the `-rpath` flag at link time.
>> For example if libgfortran.5.dylib is in fact located at
>> /opt/local/lib/libgcc/libgfortran.5.dylib in the filesystem, then when you
>> link against it with `-lgfortran` you should also specify `-rpath
>> /opt/local/lib/libgcc`.
>>
>> This all seems complicated and unnecessary to me, besides which @rpath
>> didn't exist until Mac OS X 10.5 and somehow we got along just fine without
>> it until then, therefore we usually do not choose to have libraries install
>> themselves with @rpath-based install_names (they should use simple absolute
>> path install_names instead) but I understand that the developers of gcc
>> recently decided to use @rpath here, though I do not understand why or
>> whether we can somehow still tell it not to do that.
>
> Thanks for this clear explanation.
>
> I have tried adding -rpath ${prefix}/lib/${gccdir} in Octave Portfile, but
> then I get into this problem:
>
> :info:build libtool: warning: ignoring multiple '-rpath's for a libtool
> library
>
> [...]
>
> :info:build clang: error: no such file or directory:
> '/opt/local/lib/gcc-devel/liboctave.8.dylib'
>
> Indeed, there was already a -rpath /opt/local/lib/octave/6.4.0, and adding
> -rpath with gcc apparently then prevents from finding liboctave...
>
> I have no idea how to fix this.
-rpath flags, in the way I described, are processed by the linker, and the
linker has no problem with multiple -rpath flags.
libtool also uses -rpath flags for its own purposes and expects there to be
only one.
You can encode the -rpath flags that we want to send to the linker with the -Wl
notation so that libtool will ignore them.
So instead of
-rpath ${prefix}/lib/${gccdir}
use
-Wl,-rpath,${prefix}/lib/${gccdir}
