std::aligned_alloc not available

[Nik-Sch]

I am trying to build an existing C++ project with minimal modifications and stumbled across aligned_alloc not being in the std namespace.

This works fine with non-cross-compiler g++ but does not work with x86_64-hermit-g++

#include <cstdlib>
int main() {
  void *x = std::aligned_alloc(0x1000, 0x100);
}

Compile output:

$ x86_64-hermit-g++ -Llib test.cc -std=c++23
test.cc: In function 'int main()':
test.cc:4:18: error: 'aligned_alloc' is not a member of 'std'; did you mean 'aligned_alloc'?
    4 |   void *x = std::aligned_alloc(0x1000, 0x100);
      |                  ^~~~~~~~~~~~~
In file included from /opt/hermit/x86_64-hermit/include/c++/15.1.0/cstdlib:83,
                 from test.cc:1:
/opt/hermit/x86_64-hermit/include/stdlib.h:361:9: note: 'aligned_alloc' declared here
  361 | void *  aligned_alloc(size_t, size_t) __malloc_like __alloc_align(1)

Note that it does compile when omitting the std namespace and using the C version.

Do you have any pointers for me where the problem lies?