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 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 *`).

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.

By respecting the SILENT flag when checking the visibility of a
class constant.

Remove special handling of doubles and escape them as usual instead.