[WebAssembly] Upstream misc. EH changes (#92990)

This upstreams more recent, mostly EH changes from libcxx and libcxxabi:
- `__cxa_init_primary_exception`-related changes made when updating to
LLVM 18.1.2 (https://github.com/emscripten-core/emscripten/pull/21638)
- Removes ctype macros
(https://github.com/emscripten-core/emscripten/pull/20960)
- Guard destructor changes with `__wasm__`
(https://github.com/emscripten-core/emscripten/pull/21974)

libcxx/include/__exception/exception_ptr.h

@@ -38,11 +38,14 @@ struct __cxa_exception;
 _LIBCPP_OVERRIDABLE_FUNC_VIS __cxa_exception* __cxa_init_primary_exception(
     void*,
     std::type_info*,
-    void(
 #    if defined(_WIN32)
-        __thiscall
+    void(__thiscall*)(void*)) throw();
+#    elif defined(__wasm__)
+    // In Wasm, a destructor returns its argument
+    void* (*)(void*)) throw();
+#    else
+    void (*)(void*)) throw();
 #    endif
-            *)(void*)) throw();
 }
 
 } // namespace __cxxabiv1
@@ -92,8 +95,16 @@ _LIBCPP_HIDE_FROM_ABI exception_ptr make_exception_ptr(_Ep __e) _NOEXCEPT {
   using _Ep2 = __decay_t<_Ep>;
 
   void* __ex = __cxxabiv1::__cxa_allocate_exception(sizeof(_Ep));
+#      ifdef __wasm__
+  // In Wasm, a destructor returns its argument
+  (void)__cxxabiv1::__cxa_init_primary_exception(__ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) -> void* {
+#      else
   (void)__cxxabiv1::__cxa_init_primary_exception(__ex, const_cast<std::type_info*>(&typeid(_Ep)), [](void* __p) {
+#      endif
     std::__destroy_at(static_cast<_Ep2*>(__p));
+#      ifdef __wasm__
+    return __p;
+#      endif
   });
 
   try {

libcxx/include/__locale

@@ -343,12 +343,12 @@ public:
   static const mask __regex_word = 0x4000; // 0x8000 and 0x0100 and 0x00ff are used
 #  define _LIBCPP_CTYPE_MASK_IS_COMPOSITE_PRINT
 #  define _LIBCPP_CTYPE_MASK_IS_COMPOSITE_ALPHA
-#elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__EMSCRIPTEN__) || defined(__NetBSD__)
+#elif defined(__APPLE__) || defined(__FreeBSD__) || defined(__NetBSD__)
 #  ifdef __APPLE__
   typedef __uint32_t mask;
 #  elif defined(__FreeBSD__)
   typedef unsigned long mask;
-#  elif defined(__EMSCRIPTEN__) || defined(__NetBSD__)
+#  elif defined(__NetBSD__)
   typedef unsigned short mask;
 #  endif
   static const mask space  = _CTYPE_S;

libcxxabi/include/cxxabi.h

@@ -48,13 +48,17 @@ extern _LIBCXXABI_FUNC_VIS void
 __cxa_free_exception(void *thrown_exception) throw();
 // This function is an LLVM extension, which mirrors the same extension in libsupc++ and libcxxrt
 extern _LIBCXXABI_FUNC_VIS __cxa_exception*
+#ifdef __wasm__
+// In Wasm, a destructor returns its argument
+__cxa_init_primary_exception(void* object, std::type_info* tinfo, void*(_LIBCXXABI_DTOR_FUNC* dest)(void*)) throw();
+#else
 __cxa_init_primary_exception(void* object, std::type_info* tinfo, void(_LIBCXXABI_DTOR_FUNC* dest)(void*)) throw();
+#endif
 
 // 2.4.3 Throwing the Exception Object
 extern _LIBCXXABI_FUNC_VIS _LIBCXXABI_NORETURN void
 __cxa_throw(void *thrown_exception, std::type_info *tinfo,
-#ifdef __WASM_EXCEPTIONS__
-            // In Wasm, a destructor returns its argument
+#ifdef __wasm__
             void *(_LIBCXXABI_DTOR_FUNC *dest)(void *));
 #else
             void (_LIBCXXABI_DTOR_FUNC *dest)(void *));

libcxxabi/src/cxa_exception.cpp

@@ -207,7 +207,12 @@ void __cxa_free_exception(void *thrown_object) throw() {
 }
 
 __cxa_exception* __cxa_init_primary_exception(void* object, std::type_info* tinfo,
+#ifdef __wasm__
+// In Wasm, a destructor returns its argument
+                                              void *(_LIBCXXABI_DTOR_FUNC* dest)(void*)) throw() {
+#else
                                               void(_LIBCXXABI_DTOR_FUNC* dest)(void*)) throw() {
+#endif
   __cxa_exception* exception_header = cxa_exception_from_thrown_object(object);
   exception_header->referenceCount = 0;
   exception_header->unexpectedHandler = std::get_unexpected();
@@ -267,7 +272,7 @@ will call terminate, assuming that there was no handler for the
 exception.
 */
 void
-#ifdef __WASM_EXCEPTIONS__
+#ifdef __wasm__
 // In Wasm, a destructor returns its argument
 __cxa_throw(void *thrown_object, std::type_info *tinfo, void *(_LIBCXXABI_DTOR_FUNC *dest)(void *)) {
 #else

libcxxabi/src/cxa_exception.h

@@ -43,7 +43,7 @@ struct _LIBCXXABI_HIDDEN __cxa_exception {
 
     //  Manage the exception object itself.
     std::type_info *exceptionType;
-#ifdef __WASM_EXCEPTIONS__
+#ifdef __wasm__
     // In Wasm, a destructor returns its argument
     void *(_LIBCXXABI_DTOR_FUNC *exceptionDestructor)(void *);
 #else