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.

ext/date/config0.m4

@@ -1,8 +1,14 @@
 dnl $Id$
 dnl config.m4 for date extension
 
-sinclude(ext/date/lib/timelib.m4)
-sinclude(lib/timelib.m4)
+dnl Check for headers needed by timelib
+AC_CHECK_HEADERS([ \
+strings.h \
+io.h
+])
+
+dnl Check for strtoll, atoll
+AC_CHECK_FUNCS(strtoll atoll)
 
 PHP_DATE_CFLAGS="-I@ext_builddir@/lib -DZEND_ENABLE_STATIC_TSRMLS_CACHE=1 -DHAVE_TIMELIB_CONFIG_H=1"
 timelib_sources="lib/astro.c lib/dow.c lib/parse_date.c lib/parse_tz.c