GH-160135: Support wasm32-wasip3 (#160134)

Author: brettcannon

.github/workflows/reusable-wasi.yml

@@ -16,7 +16,6 @@ jobs:
     timeout-minutes: 60
     env:
       WASMTIME_VERSION: 48.0.2
-      CROSS_BUILD_WASI: cross-build/wasm32-wasip1
     steps:
     - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
       with:
@@ -65,4 +64,6 @@ jobs:
     - name: "Display build info of the host/WASI Python"
       run: python3 Platforms/WASI pythoninfo-host
     - name: "Test"
-      run: make --directory "${CROSS_BUILD_WASI}" test
+      run: |
+        CROSS_BUILD_WASI=$(python3 Platforms/WASI path)
+        make --directory "${CROSS_BUILD_WASI}" test

Misc/NEWS.d/next/WASI/2026-10-21-15-26-12.gh-issue-160135.UP-DlO.rst

@@ -0,0 +1 @@
+Support wasm32-wasip3.

Platforms/WASI/config.toml

@@ -3,4 +3,4 @@
 # Python versions.
 [targets]
 wasi-sdk = 34
-host-triple = "wasm32-wasip1"
+host-triple = "wasm32-wasip3"