Previously:
* If only ["" => "x"] was present, the original string was returned
without warning.
* If both ["" => "x"] and at least one more element was present,
false was returned without warning.
New behavior:
* Ignore "" keys in the replacement array (and perform any remaining
replacement).
* Throw a warning indicating that an empty string replacement has
been ignored.
Closes GH-4792.
If a null $length is passed to any of these functions, behave as if no
parameter was passed:
- substr()
- substr_count()
- substr_compare()
- iconv_substr()
* get_parent_class() argument is optional
* Mark array_filter() $callback as optional
* The $base of gmp_strval() is optional
* DateTime constructor also accepts zero arguments
* hash_update_file() stream context is optional
* xmlwriter_write_dtd_entity() $isparam argument is optional
Signature stubs for internal functions are specified in xyz.stub.php,
from which we generate actual arginfo structures in xyz_arginfo.h.
This file then needs to be included in the implementation appropriately.
Arginfo from stubs can be regenerated using scripts/dev/gen_stub.php.
However, this should also automatically happen when the stub file is
modified.
