mupdf: fix library linking

[danielfullmer]

Motivation for this change

A recent change 47f0997 broke a package I maintain (k2pdfopt), which would complain about missing openssl symbols. While a quick fix would just be to link in openssl manually for my package, I believe this is the proper fix to make libmupdf behave more like a normal shared library.

Specifically, libmupdf.so does not have DT_NEEDED references to its
dependencies. Packages which link against libmupdf.so would have to also
manually link against its dependencies as well. This adds unnecessary complexity to packages which depend on it. (See also llpp, jfbview, and zathura-pdf-mupdf)

The first commit includes a patch which ensures that libmupdf.so is built with references to its own dependencies.
An additional commit fixes k2pdfopt, which uses a patched version of mupdf and requires another patch for an older version.

Output of readelf -d libmupdf.so before change:

...
0x0000000000000001 (NEEDED) Shared library: [libc.so.6]
0x000000000000001d (RUNPATH) Library runpath: [/nix/store/zpg78y1mf0di6127q6r51kgx2q8cxsvv-glibc-2.25-49/lib]
...

After change:

...
0x0000000000000001 (NEEDED) Shared library: [libmupdfthird.so]
0x0000000000000001 (NEEDED) Shared library: [libmuthreads.so]
0x0000000000000001 (NEEDED) Shared library: [libm.so.6]
0x0000000000000001 (NEEDED) Shared library: [libfreetype.so.6]
0x0000000000000001 (NEEDED) Shared library: [libharfbuzz.so.0]
0x0000000000000001 (NEEDED) Shared library: [libjbig2dec.so.0]
0x0000000000000001 (NEEDED) Shared library: [libjpeg.so.62]
0x0000000000000001 (NEEDED) Shared library: [libopenjp2.so.7]
0x0000000000000001 (NEEDED) Shared library: [libz.so.1]
0x0000000000000001 (NEEDED) Shared library: [libc.so.6]
0x000000000000000e (SONAME) Library soname: [libmupdf.so]
0x000000000000001d (RUNPATH) Library runpath: [/nix/store/05j0i5jhbp1j0mv36mj08rvn7pk7a3s4-mupdf-1.11/lib:/nix/store/7rda899md2d4q26lxb43yg3cmrgcdr1r-freetype-2.7.1/lib:/nix/store/riicxh9dp1bx90fjcf2yr7gw3wj0x7fm-harfbuzz-1.5.1/lib:/nix/store/gdnvg9j2hr4fh43arflqbzx5a86f7gpc-openjpeg-2.1.2/lib:/nix/store/i8wz3m067dzbs5x2glhxvcg7lvds1942-zlib-1.2.11/lib:/nix/store/bsqid2phn9ad8fyw2d63anzrrxp7a9x4-libjpeg-turbo-1.5.2/lib:/nix/store/0yqg15g97va4xrdzkgjd74nfxgw1c3ij-jbig2dec-0.13/lib:/nix/store/zpg78y1mf0di6127q6r51kgx2q8cxsvv-glibc-2.25-49/lib]
...

I believe llpp, jfbview, and zathura-pdf-mupdf could also be cleaned to not have to refer to mupdf's dependencies. Those packages build anyway, so it's not strictly necessary. Finally, I'm not an expert on compilers or linking so let me know if I'm misunderstanding anything.

CC @abbradar

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option build-use-sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • Linux
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[vyp]

cc mupdf maintainers: @viric @vrthra @fpletz

[abbradar]

Nice, thank you for adding a proper way to build shared mupdf!

I can test and merge this tomorrow; if anyone wants to do this sooner please go ahead.

[orivej]

I can not download mupdf-1.10a-shared_libs-1.patch from IPv6 enabled hosts because www.linuxfromscratch.org advertises an IPv6 address in the DNS but does not respond on it. Could you find another source?

[danielfullmer]

@orivej I've changed the url to a mirror which works on ipv6.

Just a note that there are some other derivations which use a linuxfromscratch.org url: id3lib, cyrus-sasl, pycairo, and even chromium.

[orivej]

Thank you! Maybe I have not downloaded them, or maybe they were already cached by nixos cache servers, or maybe linuxfromscratch IPv6 is only temporarily down.