* modules/allocator, lib/allocator.c: New files.
* lib/allocator.h (stdlib_allocator): New decl.
* lib/careadlinkat.c (_GL_USE_STDLIB_ALLOC, standard_allocator):
Remove. Do not include <stdlib.h>.
(careadlinkat): Use stdlib_allocator instead of rolling our own.
* modules/careadlinkat (Files): Remove lib/allocator.h.
(Depends-on): Add allocator.
