Build: fix linking of executables on some systems where TIFF/LCMS2 static libraries are not in system directories (fixes #1430)

[rouault]

Note that the fix might be partial only for static-only builds (cf
comments)

Ammends PR #866 and #867

CC @ffontaine / @pseiderer

[ffontaine]

I'm a little bit lost, TIFF_LIBNAME is set to ${TIFF_LIBRARIES} ${PC_TIFF_STATIC_LIBRARIES} which seems right except if ${PC_TIFF_STATIC_LIBRARIES} is "broken" on osx and contains a non existing path resulting in a build failure. Did I missed something?

[rouault]

except if ${PC_TIFF_STATIC_LIBRARIES} is "broken" on osx and contains a non existing path resulting in a build failure.

PC_TIFF_STATIC_LIBRARIES on my Ubuntu 20.04 is "tiff;webp;zstd;lzma;jbig;jpeg;z;m" . Which is OK, but this variable doesn't contain paths, which causes the issue on distributions where the libraries are not in a system library directory. Presumably this should be combined with PC_TIFF_STATIC_LIBS_PATHS to build fully expanded library names.

[ffontaine]

Thanks for the clarification. You're right, paths will not be returned by default by pkg-config, they're added by buildroot wrapper.

So, your change seems correct however I fear that it will break the build of openjp2_static when BUILD_SHARED_LIBS and BUILD_STATIC_LIBS are both set to ON. We'll probably have to disable this use case of building both libraries on buildroot.

[rouault]

I fear that it will break the build of openjp2_static when BUILD_SHARED_LIBS and BUILD_STATIC_LIBS are both set to ON

yes that's likely. Perhaps do 2 separate builds. Static builds with dependency tracking are quite difficult to get right, and openjpeg that attempts to do both at the same time make it even more challenging.

[ffontaine]

Indeed, we should definitely remove the BR2_SHARED_STATIC_LIBS option in buildroot.
Thanks for pinging me about this change. I'll be able to correctly handle the bump of openjpeg in buildroot.