I faced the issue when running josm (downloaded from
josm.openstreetmap.de, not the guix package). Using "strace" showed me
that it failed because it cannot load "libfontconfig.so" (it tries in
several directories). If I add the directory of libfontconfig.so to
LD_LIBRARY_PATH, then it starts.
I have limited knowledge about how shared libraries are found. I tried
to understand how "geany" manages to load libfontconfig.so. It looks
like it depends on libgeany, libgtk3 and libpango which depend on
libfontconfig. When I do a "readelf -a" on these libraries, I can see in
their "RUNPATH" the path of "libfontconfig.so":
0x000000000000001d (RUNPATH) Bibliothèque
runpath:[/gnu/store/avjxs6qgyginkiq6qpk9280zakkaj35h-graphite2-1.3.13/lib:/gnu/store/xwl0p4m34bcan0v9vkjkyzwi6znsv4dm-pixman-0.38.4/lib:/gnu/store/y9fdy234r6hqiacd7hgwlmbdsngbp8p1-fontconfig-2.13.1/lib:…
Regarding Java, I think (but I'm not sure) that it's loaded by
"libawt_xawt.so". In fontpath.c [1], there is a dlopen of libfontconfig.
But if I do a "ldd" on the shared library itself, it looks like it does
not depend on libfontconfig.so.
[1]
https://github.com/openjdk/jdk16/blob/37043b05576c8b81b43ac41a8f06de0d0bbb3f5b/src/java.desktop/unix/native/common/awt/fontpath.c#L566
Also libfontconfig is not on its RUNPATH:
0x000000000000001d (RUNPATH) Bibliothèque
runpath:[$ORIGIN:/gnu/store/fa6wj5bxkj5ll1d7292a70knmyl7a0cr-glibc-2.31/lib:/gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib:/gnu/store/w09mqfj1yy32r2fr02nndzs34m4f9ipp-libxext-1.3.4/lib:/gnu/store/4ildmh169dixyn05mlgjz07x4d2hcq2g-libx11-1.6.A/lib:/gnu/store/8m6368gv4z10n6i31ppbr8nxziwmlp3f-libxrender-0.9.10/lib:/gnu/store/cgsk20z1gcw78fdm7bwlb2l49xh7bmzk-libxtst-1.2.3/lib:/gnu/store/b4dk2y4vf98dhxnr0p6f5h4d86vqndkc-libxi-1.7.10/lib:/gnu/store/01b4w3m6mp55y531kyi1g8shh722kwqm-gcc-7.5.0-lib/lib/gcc/x86_64-unknown-linux-gnu/7.5.0/../../..]
I'm quite a beginner in term of Guix (I only played with it in a VM),
and I hope this information will be useful to somebody. I don't
understand how the dependencies between executable and libraries are
supposed to be done in Guix. I can see that sometimes in /gnu/store
there are symbolic links of shared libraries into other packages. I
assume that sometimes this RUNPATH is used.
