Use alignas and unions to specify alignments of objects needing
addresses that are at least a multiple of GCALIGNMENT.  Using
these standard C facilities should be safer than relying on ad hoc
and poorly-understood features like GCC’s __attribute__
((aligned (N))), the root cause for recent porting bugs like
Bug#29040.  The alignas macro was standardized by C11 and Gnulib
supports alignas for pre-C11 platforms.  I have tested this on Sun
Studio 12 sparc (2007) and GCC 4.4.7 x86-64 (2012) as well as on
more recent platforms like GCC 7.2.1 (2017) on Fedora 26 (both
x86-64 and x86).
* lib-src/make-docfile.c (close_emacs_globals): lispsym is now
just an array of struct Lisp_Symbol, since struct Lisp_Symbol is
now properly aligned.  All uses changed.
* src/alloc.c (NEXT_FREE_LISP_STRING): Just use the new u.next
member; this is simpler and safer than casting a pointer that
might not be aligned properly.
(aligned_Lisp_Symbol): Remove.  No longer needed, now that struct
Lisp_Symbol is aligned properly.  All uses replaced with struct
Lisp_Symbol.
* src/lisp.h (GCALIGNED): Remove, as it does not work as expected:
it can cause the natural alignment to be ignored.  All uses
replaced by unions with a ‘char alignas (GCALIGNMENT)’ member as
described below.
(struct Lisp_Symbol, struct Lisp_Cons, struct Lisp_String):
Change definition from ‘struct TAG { MEMBERS };’ to
‘struct TAG { union { struct { MEMBERS } s; char alignas
(GCALIGNMENT) gcaligned; } u; };’.  This guarantees ‘struct TAG’
to have an alignment that at least max (GCALIGNMENT, N) where N is
its old alignment.  All uses like ‘PTR->MEMBER’ changed to
‘PTR->u.s.MEMBER’; these uses were supposed to be mostly private
anyway.  Verify that the resulting ‘struct TAG’ is properly
aligned for Emacs.
(union vectorlike_header): New member ‘gcaligned’ to guarantee
that this type, and its containing types like ‘struct Lisp_Subr’,
‘struct buffer’ and ‘struct thread_state’, are all properly
aligned for Emacs.
(struct Lisp_String): New union member ‘next’, for the benefit
of NEXT_FREE_LISP_STRING.
(union Aligned_Cons, union Aligned_String): Remove.  All uses
replaced by struct Lisp_Cons and struct Lisp_String, since they
are now properly aligned.
(USE_STACK_CONS, USE_STACK_STRING): Simplify now that we can
assume struct Lisp_Cons and struct Lisp_String are properly
aligned.

Apparently GCC requires that ‘__attribute__ ((aligned (8)))’ must
immediately follow the ‘struct’ keyword when aligning a structure.
The attribute silently does not work if it follows a tag after the
‘struct’ keyword.  Who knew?  Anyway, this patch is designed to
fix a SIGSEGV problem reported by John Mastro (Bug#29183).
* lib-src/make-docfile.c (close_emacs_globals):
* src/buffer.c (buffer_defaults, buffer_local_symbols):
* src/lisp.h (DEFUN):
* src/thread.c (main_thread):
Put 'GCALIGNED' immediately after 'struct'.

Do not assume that the natural alignment of Lisp objects is a
multiple of GCALIGNMENT.  This improves on the portability of the
recent fix for Bug#29040.
* lib-src/make-docfile.c (close_emacs_globals):
* src/buffer.c (buffer_defaults, buffer_local_symbols):
* src/lisp.h (DEFUN):
* src/thread.c (main_thread):
Use GCALIGNED, not alignas (GCALIGNMENT).
* src/alloc.c (COMMON_MULTIPLE):
Move back here from lisp.h, since it is no longer used elsewhere.
* src/lisp.h (GCALIGNMENT): No longer a macro, since we need not
worry about MSVC.  Omit no-longer-needed consistency check.
* src/thread.c (THREAD_ALIGNMENT): Remove.

* lisp/cedet/semantic/analyze/refs.el:
(semantic-analyze-proto-impl-toggle): Fix recently-introduced
misspelling of pop-to-buffer-same-window.

* src/process.c (Fmake_network_process):
* src/image.c (xbm_scan, gif_load):
* src/fileio.c (Frename_file):
* src/data.c (Fmake_local_variable):
* src/buffer.c (fix_start_end_in_overlays):
* lib-src/etags.c (process_file_name): Mark variables with UNINIT
to avoid compiler warnings in optimized builds.

This fixes some URLs I omitted from my previous pass,
notably those in lists.gnu.org.  Although lists.gnu.org
does not yet support TLS 1.1, TLS 1.0 is better than nothing.
* lisp/erc/erc.el (erc-official-location):
* lisp/mail/emacsbug.el (report-emacs-bug):
Use https:, not http:.

This is mostly to change http: to https: in licenses.
* COPYING, build-aux/config.guess, build-aux/config.sub:
* doc/emacs/doclicense.texi, doc/emacs/gpl.texi:
* doc/lispintro/doclicense.texi, doc/lispref/doclicense.texi:
* doc/lispref/gpl.texi, doc/misc/doclicense.texi:
* doc/misc/gpl.texi, etc/COPYING, leim/COPYING:
* lib-src/COPYING, lib/COPYING, lisp/COPYING, lwlib/COPYING:
* msdos/COPYING, nt/COPYING, src/COPYING:
Copy from Gnulib.

This catches some URLs I missed in my previous scan,
or perhaps were added after the scan.

* lib-src/etags.c (etags_mktmp) [DOS_NT]: Don't dereference a NULL
pointer.  Reported by Richard Copley <rcopley@gmail.com>.