Re: wip/librsvg (rust): failure in link step

[maya%netbsd.org@localhost]

Some notes I had, to consider further investigation:

(1) rsvg_internals/Cargo.toml, there are several types of crate-type
that can be used.  I am not sure I tested all.

(2) the functions that appear in errors, when inspecting 'readelf -a'
librsvg_internals.so: function appears in .dynsym and .symtab

comparing to libc.so:
functions appear in .dynsym, .symtab and .rela.plt.

(3) .work.log suggests some unusual linker flags like --gc-sections and
a version script.
A version script can make some symbols hidden.
However they are temporary files and deleted (-save-temps might be
usable somehow)

(4) it fails outside of pkgsrc too

(5) Some of the rust link flags originate from
https://github.com/rust-lang/rust/blob/936b32a514b73c1d3dfcbd9d17818f9f18bf4883/src/librustc_back/target/netbsd_base.rs
where other OSes appear, for comparison.

All of the testing is on NetBSD.