Build #12's instrumented pthread_shim gave us the definitive diagnosis:
WZP_pthread_shim: dlsym(RTLD_DEFAULT, pthread_create) returned NULL:
libdl.a is a stub --- use libdl.so instead
Tauri-cli invokes `aarch64-linux-android24-clang` as the linker and the
API-24 NDK sysroot ships *stub* libdl.a / libc.a: they compile fine but
every symbol crashes if called, because they're meant to coexist with a
separate dynamic .so that the dynamic linker provides at runtime. Rust's
pre-built libstd.rlib has static calls into those stubs baked in, so no
matter what we do at link time the broken code lands in the .so.
Env-var overrides of CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER don't
stick — tauri-cli resets them before invoking cargo. So instead of
fighting the env, we put a wrapper on $PATH, literally named
`aarch64-linux-android24-clang`, that exec()s the android26 version.
When tauri-cli looks up android24-clang via PATH, it gets our wrapper,
our wrapper runs android26-clang, and suddenly the whole build is using
the API-26 NDK sysroot with real dynamic bindings to libc.so / libdl.so.
Wrappers are installed for all four ABIs (aarch64, armv7, x86_64, i686)
× both suffixes (clang, clang++) directly inside the docker bash -c
preamble before any cargo invocation.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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