* lib/safe-alloc.c: Do not include xalloc-oversized.h.
(safe_alloc_alloc_n, safe_alloc_realloc_n):
Use reallocarray to check for size or ptrdiff_t overflow.
* modules/reallocarray (License): Switch from LGPL to LGPLv2+, as
this is needed for safe-alloc and anyway is more appropriate for
this library function common with BSD.
* modules/safe-alloc (Depends-on): Depend on reallocarray
rather than xalloc-oversized.
reallocarray is a new function in glibc 2.26 to safely allocate an array
of memory locations with integer overflow protection.
* MODULES.html.sh: Add reallocarray.
* doc/glibc-functions/reallocarray.texi: Documentation for reallocarray.
* lib/reallocarray.c: New file to implement module reallocarray.
* lib/stdlib.in.h: Add function declarations for reallocarray.
* m4/reallocarray.m4: New file.
* m4/stdlib_h.m4: Declare reallocarray.
* modules/reallocarray: New file.
* modules/reallocarray-test: New file.
* modules/stdlib: Coerce stdlib.h to export reallocarray.
* tests/test-reallocarray.c: New test.