Description:
------------
In ext/date/lib/timelib_struct.h you have:

typedef struct _timelib_tz_lookup_table {
	char       *name;
	int         type;
	int         gmtoffset;
	char       *full_tz_name;
} timelib_tz_lookup_table;

But in ext/date/lib/fallbackmap.h you can notice some timezones are declared with offsets non-integer like:
	{ "ist",   0,  5.5,  "Asia/Calcutta" },

This break get_default_timezone function that reverts to UTC for those values that are non-integer. The fix is easy, just change gmtoffset to float:

typedef struct _timelib_tz_lookup_table {
	char       *name;
	int         type;
	int         gmtoffset;
	char       *full_tz_name;
} timelib_tz_lookup_table;

I've tested under Visual Studio 2005 Express and with this change date_default_timezone_get() works fine now.

If there is a place to send patches, please tell me and I'll gladly submit.

Reproduce code:
---------------
Run date_default_timezone_get() in a Windows machine with a non-integer timezone (for example calcutah +5:30)

Expected result:
----------------
Shold return IST

Actual result:
--------------
Returns UTC