pythonGH-142234: Allow --enable-wasm-dynamic-linking under WASI (pythonGH-142235)

While CPython doesn't support `--enable-wasm-dynamic-linking`, external tools like componentize-py do and they have to patch around it. Since the flag is off by default, allowing the flag so external users can add/inject dynamic linking support seems acceptable.

Author: brettcannon

Misc/NEWS.d/next/Build/2025-12-03-10-44-42.gh-issue-142234.i1kaFb.rst

@@ -0,0 +1,3 @@
+Allow ``--enable-wasm-dynamic-linking`` for WASI. While CPython doesn't
+directly support it so external/downstream users do not have to patch in
+support for the flag.

configure

@@ -1306,11 +1306,11 @@ dnl See https://emscripten.org/docs/compiling/Dynamic-Linking.html
 AC_MSG_CHECKING([for --enable-wasm-dynamic-linking])
 AC_ARG_ENABLE([wasm-dynamic-linking],
   [AS_HELP_STRING([--enable-wasm-dynamic-linking],
-                  [Enable dynamic linking support for WebAssembly (default is no)])],
+                  [Enable dynamic linking support for WebAssembly (default is no); WASI requires an external dynamic loader to handle imports])],
 [
   AS_CASE([$ac_sys_system],
     [Emscripten], [],
-    [WASI], [AC_MSG_ERROR([WASI dynamic linking is not implemented yet.])],
+    [WASI], [],
     [AC_MSG_ERROR([--enable-wasm-dynamic-linking only applies to Emscripten and WASI])]
   )
 ], [