Fix C++ function signatures in mimalloc (#21127)

The C++ functions that take `std::nothrow_t` all take a reference.
Without this change I'm seeing function signature mismatches because the
final argument is not pointer-width.  I'm guessing this simply went
unnoticed because most platforms don't do signature checking in the
linker and this just happens to work.

e.g.  `_ZnwjRKSt9nothrow_t` which demangles to `operator new(unsigned
int, std::nothrow_t const&)`

See upstream bug at microsoft/mimalloc#840.

system/lib/mimalloc/src/alloc-override.c

@@ -108,8 +108,9 @@ typedef struct mi_nothrow_s { int _tag; } mi_nothrow_t;
   void  _ZdaPvm(void* p, size_t n);  // delete[]
   void* _Znwm(size_t n);  // new
   void* _Znam(size_t n);  // new[]
-  void* _ZnwmRKSt9nothrow_t(size_t n, mi_nothrow_t tag); // new nothrow
-  void* _ZnamRKSt9nothrow_t(size_t n, mi_nothrow_t tag); // new[] nothrow
+  // XXX EMSCRIPTEN: Use pointer type for nothrow argument
+  void* _ZnwmRKSt9nothrow_t(size_t n, mi_nothrow_t* tag); // new nothrow
+  void* _ZnamRKSt9nothrow_t(size_t n, mi_nothrow_t* tag); // new[] nothrow
   #ifdef __cplusplus
   }
   #endif
@@ -201,21 +202,23 @@ typedef struct mi_nothrow_s { int _tag; } mi_nothrow_t;
   #if (MI_INTPTR_SIZE==8)
     void* _Znwm(size_t n)                             MI_FORWARD1(mi_new,n)  // new 64-bit
     void* _Znam(size_t n)                             MI_FORWARD1(mi_new,n)  // new[] 64-bit
-    void* _ZnwmRKSt9nothrow_t(size_t n, mi_nothrow_t tag) { MI_UNUSED(tag); return mi_new_nothrow(n); }
-    void* _ZnamRKSt9nothrow_t(size_t n, mi_nothrow_t tag) { MI_UNUSED(tag); return mi_new_nothrow(n); }
+    // XXX EMSCRIPTEN: Use pointer type for nothrow argument
+    void* _ZnwmRKSt9nothrow_t(size_t n, mi_nothrow_t* tag) { MI_UNUSED(tag); return mi_new_nothrow(n); }
+    void* _ZnamRKSt9nothrow_t(size_t n, mi_nothrow_t* tag) { MI_UNUSED(tag); return mi_new_nothrow(n); }
     void* _ZnwmSt11align_val_t(size_t n, size_t al)   MI_FORWARD2(mi_new_aligned, n, al)
     void* _ZnamSt11align_val_t(size_t n, size_t al)   MI_FORWARD2(mi_new_aligned, n, al)
-    void* _ZnwmSt11align_val_tRKSt9nothrow_t(size_t n, size_t al, mi_nothrow_t tag) { MI_UNUSED(tag); return mi_new_aligned_nothrow(n,al); }
-    void* _ZnamSt11align_val_tRKSt9nothrow_t(size_t n, size_t al, mi_nothrow_t tag) { MI_UNUSED(tag); return mi_new_aligned_nothrow(n,al); }
+    void* _ZnwmSt11align_val_tRKSt9nothrow_t(size_t n, size_t al, mi_nothrow_t* tag) { MI_UNUSED(tag); return mi_new_aligned_nothrow(n,al); }
+    void* _ZnamSt11align_val_tRKSt9nothrow_t(size_t n, size_t al, mi_nothrow_t* tag) { MI_UNUSED(tag); return mi_new_aligned_nothrow(n,al); }
   #elif (MI_INTPTR_SIZE==4)
     void* _Znwj(size_t n)                             MI_FORWARD1(mi_new,n)  // new 64-bit
     void* _Znaj(size_t n)                             MI_FORWARD1(mi_new,n)  // new[] 64-bit
-    void* _ZnwjRKSt9nothrow_t(size_t n, mi_nothrow_t tag) { MI_UNUSED(tag); return mi_new_nothrow(n); }
-    void* _ZnajRKSt9nothrow_t(size_t n, mi_nothrow_t tag) { MI_UNUSED(tag); return mi_new_nothrow(n); }
+    // XXX EMSCRIPTEN: Use pointer type for nothrow argument
+    void* _ZnwjRKSt9nothrow_t(size_t n, mi_nothrow_t* tag) { MI_UNUSED(tag); return mi_new_nothrow(n); }
+    void* _ZnajRKSt9nothrow_t(size_t n, mi_nothrow_t* tag) { MI_UNUSED(tag); return mi_new_nothrow(n); }
     void* _ZnwjSt11align_val_t(size_t n, size_t al)   MI_FORWARD2(mi_new_aligned, n, al)
     void* _ZnajSt11align_val_t(size_t n, size_t al)   MI_FORWARD2(mi_new_aligned, n, al)
-    void* _ZnwjSt11align_val_tRKSt9nothrow_t(size_t n, size_t al, mi_nothrow_t tag) { MI_UNUSED(tag); return mi_new_aligned_nothrow(n,al); }
-    void* _ZnajSt11align_val_tRKSt9nothrow_t(size_t n, size_t al, mi_nothrow_t tag) { MI_UNUSED(tag); return mi_new_aligned_nothrow(n,al); }
+    void* _ZnwjSt11align_val_tRKSt9nothrow_t(size_t n, size_t al, mi_nothrow_t* tag) { MI_UNUSED(tag); return mi_new_aligned_nothrow(n,al); }
+    void* _ZnajSt11align_val_tRKSt9nothrow_t(size_t n, size_t al, mi_nothrow_t* tag) { MI_UNUSED(tag); return mi_new_aligned_nothrow(n,al); }
   #else
     #error "define overloads for new/delete for this platform (just for performance, can be skipped)"
   #endif