The `<assert.h>` header file is part of the standard C89 headers [1] and
on older systems there needed to be also a manual check if header is
present.
Since PHP requires at least C89 manual check and the `HAVE_ASSERT_H`
symbol defined by Autoconf in configure.ac can be both removed [2].
This patch also removes unused <assert.h> includes where c files don't
use the `assert()` macro.
Refs:
[1] https://port70.net/~nsz/c/c89/c89-draft.html#4.2
[2] https://git.savannah.gnu.org/cgit/autoconf.git/tree/lib/autoconf/headers.m4
The $Id$ keywords were used in Subversion where they can be substituted
with filename, last revision number change, last changed date, and last
user who changed it.
In Git this functionality is different and can be done with Git attribute
ident. These need to be defined manually for each file in the
.gitattributes file and are afterwards replaced with 40-character
hexadecimal blob object name which is based only on the particular file
contents.
This patch simplifies handling of $Id$ keywords by removing them since
they are not used anymore.
