There have been multiple reports of large slowdowns due to the
use of MADV_HUGEPAGE, so make it conditional on
USE_ZEND_ALLOC_HUGE_PAGES, just like MAP_HUGETLB already is.

We apply only the most minimal fix here, and will cater to the
unnecessary re-allocation for PHP-7.4.

We don't need to add a regression test, since bug39606.phpt and
bug77621.phpt already show the misbehavior.

* PHP-7.2:
  Fix #77621: Already defined constants are not properly reported

We must not check uninitialized values (i.e. `c.value`), and we have to
use proper types for printf-style formats (i.e. `char *` instead of
`zend_string *`).

Port php_setcookie() to use the smart_str API to ensure that there
can be no string truncation issues.

* PHP-7.2:
  Refactor timelib.m4

The ext/date/lib is bundled library and also includes additional
timelib.m4 macros and checks specific for PHP.

All the checks in the timelib.m4 are already done in the PHP's
configure.ac:
- headers except for io.h and strings.h
- two functions checked strftime and gettimeofday
- if size of longint is 8
- if size of int is 4
- int32_t and uint32_t types using the PHP_CHECK_STDINT_TYPES

Macro `AC_TIMELIB_C_BIGENDIAN` defined in timelib.m4 is not used.

The two checkings for strtoll and atoll have been moved to date extension's
config0.m4 file.

Additional check for headers <io.h> and <strings.h> has been added to
config0.m4 of the date extension.

Therefore the timelib.m4 can be simplified and removed from the bundled
library to have easier maintenance in the later branches and also
upstream library.