Re: AC_LIB_HAVE_LINKFLAGS: linking with static library on macOS

[Mohammad Akhlaghi]

On 5/26/19 12:42 AM, Bruno Haible wrote:
> > /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ranlib:
> > archive member: .libs/libgnuastro.a(libcfitsio.a) fat file for cputype
> > (7) cpusubtype (3) is not an object file (bad magic number)
> > /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ar:
> > internal ranlib command failed
>
> This error does not involve any GNU tools tools or libraries. It only
> involves the Apple tools and /usr/local stuff (MacPorts or Homebrew?).
> You find the answer on stackoverflow.com:
> https://stackoverflow.com/questions/54363030/cannot-install-any-version-of-ruby-on-mojave-internal-ranlib-command-failed/54936974

I think the Mac system in question uses Homebrew (its not mine!).

> > After some investigation, I came up with [1] which says: "The root cause
> > of it is what we provide static libraries on OS X only in fat(Universal
> > binary) format and GNU libtool does not know anything about it. Our
> > recommendation here is to use libtool which is provided by Apple in
> > XCode.".
>
> It is true that the GNU build system does not support building fat
> binaries. Installing the GNU binutils would not help either. You can
> build fat binaries only by building one binary per arch and then
> glueing them together using the Apple tool ('lipo' or some such).
>
> The text you cited sounds like Apple libtool is a replacement for
> GNU libtool. This would be nonsense. There is no need to invoke
> Apple's libtool. Use GNU libtool to create shared libraries.

Indeed, I was thinking that GNU Libtool and Mac's Libtool aren't 
inter-changable and was a little puzzled by the text I quoted. Thanks 
for the confirmation.

Generally, to avoid such crashes during the build, what do you think 
about adding a check in `AC_LIB_HAVE_LINKFLAGS' to test this scenario 
(see if the used libtool can link with the found static library)? 
Getting a notice/warning/crash at configure time is much easier for a 
user than during build time.

Thanks a lot,
Mohammad