Review conf_wasm.py: fix ERRNO_CODES, WASI CFLAGS, and dlopen logic.

- _setup_emscripten_flags: add missing ERRNO_CODES to
  -sEXPORTED_RUNTIME_METHODS, matching configure.ac line 2368.
- _setup_wasi_flags: also append -target wasm32-wasi-threads -pthread
  to CFLAGS (not just CFLAGS_NODIST); the comment explains this is
  needed so ac_compile/ac_link tests succeed during configure.
- setup_wasm_flags: fix ac_cv_func_dlopen logic: use == "no" instead
  of "is False" so that explicit --enable-wasm-dynamic-linking=no
  suppresses dlopen (matching configure.ac), and "missing" (no option
  given) correctly leaves dlopen unprobed.

Assisted-by: Claude

Author: nascheme

Tools/configure/conf_wasm.py

@@ -74,7 +74,7 @@ def setup_wasm_flags(v):
     # Force/suppress ac_cv_func_dlopen for WASM dynamic linking
     if v.enable_wasm_dynamic_linking == "yes":
         v.ac_cv_func_dlopen = True
-    elif v.enable_wasm_dynamic_linking is False:
+    elif v.enable_wasm_dynamic_linking == "no":
         v.ac_cv_func_dlopen = False
 
     # Ensure variables exist even on non-WASM builds
@@ -115,7 +115,7 @@ def _setup_emscripten_flags(v):
         " -sFORCE_FILESYSTEM -lidbfs.js -lnodefs.js -lproxyfs.js -lworkerfs.js"
     )
     v.LINKFORSHARED += (
-        " -sEXPORTED_RUNTIME_METHODS=FS,callMain,ENV,HEAPU32,TTY"
+        " -sEXPORTED_RUNTIME_METHODS=FS,callMain,ENV,HEAPU32,TTY,ERRNO_CODES"
     )
     v.LINKFORSHARED += (
         " -sEXPORTED_FUNCTIONS=_main,_Py_Version,__PyRuntime,"
@@ -173,6 +173,7 @@ def _setup_wasi_flags(v):
         # Note: wasi requires --export-memory.
         # Note: --export-memory is implicit unless --import-memory is given
         # Note: this requires LLVM >= 16.
+        v.CFLAGS += " -target wasm32-wasi-threads -pthread"
         v.CFLAGS_NODIST += " -target wasm32-wasi-threads -pthread"
         v.LDFLAGS_NODIST += (
             " -target wasm32-wasi-threads -pthread"

Tools/configure/configure.awk

@@ -8762,7 +8762,7 @@ function u__setup_emscripten_flags(    WASM_LINKFORSHARED_DEBUG) {
     V["LINKFORSHARED"] = V["LINKFORSHARED"] " -sALLOW_MEMORY_GROWTH -sINITIAL_MEMORY=20971520"
     V["LDFLAGS_NODIST"] = V["LDFLAGS_NODIST"] " -sWASM_BIGINT"
     V["LINKFORSHARED"] = V["LINKFORSHARED"] " -sFORCE_FILESYSTEM -lidbfs.js -lnodefs.js -lproxyfs.js -lworkerfs.js"
-    V["LINKFORSHARED"] = V["LINKFORSHARED"] " -sEXPORTED_RUNTIME_METHODS=FS,callMain,ENV,HEAPU32,TTY"
+    V["LINKFORSHARED"] = V["LINKFORSHARED"] " -sEXPORTED_RUNTIME_METHODS=FS,callMain,ENV,HEAPU32,TTY,ERRNO_CODES"
     V["LINKFORSHARED"] = V["LINKFORSHARED"] " -sEXPORTED_FUNCTIONS=_main,_Py_Version,__PyRuntime,_PyGILState_GetThisThreadState,__Py_DumpTraceback,__PyEM_EMSCRIPTEN_TRAMPOLINE_OFFSET"
     V["LINKFORSHARED"] = V["LINKFORSHARED"] " -sSTACK_SIZE=5MB"
     V["LINKFORSHARED"] = V["LINKFORSHARED"] " -sTEXTDECODER=2"
@@ -8790,6 +8790,7 @@ function u__setup_wasi_flags() {
     pyconf_define("_WASI_EMULATED_PROCESS_CLOCKS", 1, 0, "Define to 1 if you want to emulate process clocks on WASI")
     V["LIBS"] = V["LIBS"] " -lwasi-emulated-signal -lwasi-emulated-getpid -lwasi-emulated-process-clocks"
     if ((V["enable_wasm_pthreads"] == "yes")) {
+        V["CFLAGS"] = V["CFLAGS"] " -target wasm32-wasi-threads -pthread"
         V["CFLAGS_NODIST"] = V["CFLAGS_NODIST"] " -target wasm32-wasi-threads -pthread"
         V["LDFLAGS_NODIST"] = V["LDFLAGS_NODIST"] " -target wasm32-wasi-threads -pthread -Wl,--import-memory -Wl,--export-memory -Wl,--max-memory=10485760"
     }