Fix crash in Time on 32-bit systems

	[Bug #19575]

	struct vtm is packed causing it to have a size that is not aligned on
	32-bit systems. When allocating it on the stack, it will have unaligned
	addresses which means that the fields won't be marked by the GC when
	scanning the stack (since the GC only marks aligned addresses). This can
	cause crashes when the fields are heap allocated objects like Bignums.

	This commit moves the flags in struct time_object into struct vtm for
	space efficiency and removes the need for packing.

	This is an example of a crash:

	    ruby(rb_print_backtrace+0xd) [0x56848945] ../src/vm_dump.c:785
	    ruby(rb_vm_bugreport) ../src/vm_dump.c:1101
	    ruby(rb_assert_failure+0x7a) [0x56671857] ../src/error.c:878
	    ruby(vm_search_cc+0x0) [0x56666e47] ../src/vm_method.c:1366
	    ruby(rb_vm_search_method_slowpath) ../src/vm_insnhelper.c:2090
	    ruby(callable_method_entry+0x5) [0x568232d3] ../src/vm_method.c:1406
	    ruby(rb_callable_method_entry) ../src/vm_method.c:1413
	    ruby(gccct_method_search_slowpath) ../src/vm_eval.c:427
	    ruby(gccct_method_search+0x20f) [0x568237ef] ../src/vm_eval.c:476
	    ruby(opt_equality_by_mid_slowpath+0x2c) [0x5682388c] ../src/vm_insnhelper.c:2338
	    ruby(rb_equal+0x37) [0x566fe577] ../src/object.c:133
	    ruby(rb_big_eq+0x34) [0x56876ee4] ../src/bignum.c:5554
	    ruby(rb_int_equal+0x14) [0x566f3ed4] ../src/numeric.c:4640
	    ruby(rb_int_equal) ../src/numeric.c:4634
	    ruby(vm_call0_cfunc_with_frame+0x6d) [0x568303c2] ../src/vm_eval.c:148
	    ruby(vm_call0_cfunc) ../src/vm_eval.c:162
	    ruby(vm_call0_body) ../src/vm_eval.c:208
	    ruby(rb_funcallv_scope+0xd1) [0x56833971] ../src/vm_eval.c:85
	    ruby(RB_TEST+0x0) [0x567e8488] ../src/time.c:78
	    ruby(eq) ../src/time.c:78
	    ruby(small_vtm_sub) ../src/time.c:1523
	    ruby(timelocalw+0x23b) [0x567f3e9b] ../src/time.c:1593
	    ruby(time_s_alloc+0x0) [0x567f536b] ../src/time.c:3698
	    ruby(time_new_timew) ../src/time.c:2694
	    ruby(time_s_mktime) ../src/time.c:3698
	---
	 test/ruby/test_time.rb |  7 ++-----
	 time.c                 | 57 ++++++++++++++++++++++++--------------------------
	 timev.h                |  7 +++++--
	 3 files changed, 34 insertions(+), 37 deletions(-)

Saves comitters' daily life by avoid #include-ing everything from
internal.h to make each file do so instead.  This would significantly
speed up incremental builds.

We take the following inclusion order in this changeset:

1.  "ruby/config.h", where _GNU_SOURCE is defined (must be the very
    first thing among everything).
2.  RUBY_EXTCONF_H if any.
3.  Standard C headers, sorted alphabetically.
4.  Other system headers, maybe guarded by #ifdef
5.  Everything else, sorted alphabetically.

Exceptions are those win32-related headers, which tend not be self-
containing (headers have inclusion order dependencies).

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67502 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

Because hard to specify commits related to r67479 only.
So please commit again.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67499 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67491 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

* strftime.c (rb_strftime): support timezone object by `%z`.

* time.c (time_init_1, time_new_timew, time_getlocaltime): accept
  timezone object as `off`.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64952 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64834 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64833 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

This removes zone_table and use fstring instead.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64227 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

There's no point in having separate types depending on C dialect
when using bitfields, "unsigned int" bitfields are bitfields
anywhere.

Note: we also have test_memsize in test_time.rb in case
users of other platforms want to enable size assertions
if they don't trust their compiler.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61870 b2dd03c8-39d4-4d8f-98ff-823fe69b080e