* PHP-7.3:
  Resolve discrepencies between second value yielded by gettimeofday and time, fixes #69044

Function strftime is part of the C89 standard [1] and current systems
don't need to check for its presence anymore.

Additionally, checks for strftime function in tests have been removed
since the PHP strftime function is now always available.

1: https://port70.net/~nsz/c/c89/c89-draft.html

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.