Exclude or fix wasm platform

[gregorgorjanc]

https://highlanderlab.r-universe.dev/RcppTskitTestLinking reporst one fail due to wasm platform. Can me drop or fix that platform somehow?

[gregorgorjanc]

Here are some suggestions from Codex, that we should look into:

The wasm failure isn’t because tskit can’t run on wasm; it’s because RcppTskit only exposes a native shared object path for linking. In a cross‑compile build, that path resolves to an x86_64 .so, and wasm-ld rejects it. To make RcppTskit wasm‑ready, change it to ship a wasm‑linkable static archive and expose wasm‑aware link flags instead of an absolute .so path.

Here’s what I’d change in RcppTskit:

Build and install a static archive (libRcppTskit.a) alongside the shared lib
Add an all target to create the archive from $(OBJECTS) and an install target to copy it into $(R_PACKAGE_DIR)/libs
Files: Makevars.in, RcppTskit/cleanup, cleanup.win
Make link flags wasm‑aware and avoid absolute .so on wasm
Provide RcppTskit::LdFlags() (and optionally CxxFlags()), returning -L<libdir> -lRcppTskit when target is wasm
Keep the current absolute‑path behavior for native platforms
Files: RcppTskit-package.R (plugin) + new helper in R/ for LdFlags()
Skip -soname/-install_name on wasm
Those are ELF/Mach‑O specific; for wasm they’re useless and can confuse wasm-ld
File: configure.R