bug#36172: 27.0.50; linking error in git head on macos: _aligned_alloc

[Paul Eggert]

'configure' says you have aligned_alloc, because it successfully built 
an executable that calls aligned_alloc. However, the dynamic linker 
fails, in that when temacs runs and calls aligned_alloc, its dynamic 
linker fails to find an implementation. Please figure out why that is. 
For example, you can compile and run this program with the same flags 
you use to compile Emacs:

  #include <stdlib.h>

  int
  main (int argc, char **argv)
  {
    char *p = aligned_alloc (8, 1);
    char *q = aligned_alloc (8, 2);
    return p && q && p == q;
  }

If it compiles and runs successfully, you can then investigate why it 
works but temacs doesn't. Otherwise, you can investigate why it doesn't 
work.