Fix some problems with negative and out-of-range integers.

Fix some problems with negative and out-of-range integers.

Original problem reported for HP-UX LVM v2.2 by Michael White in
<http://lists.gnu.org/archive/html/bug-tar/2012-10/msg00000.html>.
This patch fixes some other gotchas that I noticed.
* gnulib.modules: Add extern-inline.
* src/common.h: Use _GL_INLINE_HEADER_BEGIN, _GL_INLINE_HEADER_END.
(COMMON_INLINE, max, min): New macros.
(represent_uintmax, valid_timespec): New inline functions.
(SYSINT_BUFSIZE): New constant.
(sysinttostr, strtosysint, decode_timespec): New decls.
* src/create.c (start_private_header): Silently bring the time_t
value into range; it is now the caller's responsibility to deal
with any overflow error.  Use uid 0 and gid 0 rather than the
user's uid/gid, since the faked header isn't "owned" by the user
and the uid/gid could in theory be out of range.  Leave major and
minor zeroed.
(FILL): Remove.
(write_gnu_long_link): Let start_private_header zero things out.
* src/create.c (write_gnu_long_link, write_extended):
* src/xheader.c (xheader_write_global):
Use start_time, not current time; no point hammering on the clock.
* src/compare.c (diff_multivol): Check that offset, size are in range.
* src/incremen.c (read_incr_db_01, write_directory_file_entry):
Allow negative time_t, dev_t, and ino_t.
* src/list.c (max): Remove (moved to common.h).
(read_header): Check that size is in range.
(from_header): Return intmax_t, not uintmax_t, to allow negative.
All callers changed.  At compile time, check assumptions about
intmax_t and uintmax_t.  Use bool for booleans.  Avoid overflow
hassles on picky hosts.
(mode_from_header): Last arg is now bool *, not unsigned *.
All callers changed.
(simple_print_header): Do not assume UID, GID fit in 'long'.
* src/list.c (from_header):
* src/xheader.c (out_of_range_header):
Arg is now a plain minimum value, not minus minval converted to
uintmax_t.  All callers changed.
* src/misc.c (COMMON_INLINE): New macro.
(sysinttostr, strtosysint, decode_timespec): New functions.
* src/sparse.c (oldgnu_add_sparse, oldgnu_fixup_header)
(star_fixup_header):
Check for offset overflow.
(decode_num): Clear errno before calling strtoumax.
* src/tar.c (expand_pax_option): Don't discard nanoseconds.
* src/xheader.c (assign_time_option): Allow negative time_t.
(decode_record): Simplify, since out-of-range string is guaranteed
to produce a value exceeding len_max.
(xheader_read): Last arg is off_t, not size_t.
Caller should diagnose negative arg, as needed.
Check that it's in range.
(enum decode_time_status): Remove.
(_decode_time): Remove, folding into decode_time.
(decode_time): Return bool, not enum decode_time_status.
Rely on decode_timespec to do most of the work.
(code_signed_num): New function.
(code_num): Use it.
(decode_signed_num): New function.
(decode_num): Use it.
(gid_coder, gid_decoder, uid_coder, uid_decoder, sparse_map_decoder)
(sparse_map_decoder): Code and decode negative values.
(sparse_map_decoder): Improve check for out-of-range values.
* tests/time01.at: New file.
* tests/Makefile.am (TESTSUITE_AT): Add it.
* tests/testsuite.at: Include it.