* src/android.c (struct android_thread_event_queue): New
structure.  Move global pselect arguments, mutexes, and
semaphores, and pipes here.
(struct android_event_queue) <select_mutex, select_thread>:
Remove to the above-named struct.
(android_init_thread_events, android_finalize_thread_events)
(android_get_poll_thread): New functions.
(android_run_select_thread): Accept a set of mutexes and
thread-local data as the first argument, and operate with them
rather than globals.
(android_handle_sigusr1): Rename to
`android_handle_poll_signal'.  Set thread-specific cancellation
indicator.
(android_init_events): Properly abort after a fatal condition.
Enable interruptible polling on Android 5.1 and later, not 4.2.
(android_select): Never check for queries here, but in
thread_select, if threads are enabled.  Adapt to per-thread
polling threads and only enable interruptible polling on Android
5.1 and later.
(android_before_select): New function.

* src/android.h (android_before_select): New declaration.

* src/thread.c (thread_select): Call `android_before_select'
before the global lock is released.

* src/bytecode.c (bcall0):
* src/comp.c (bcall0):
* src/eval.c (apply1):
* src/lisp.h (call0):
* src/thread.c (invoke_thread_function): Use calln instead of calling
Ffuncall directly.

* admin/coccinelle/calln.cocci: New semantic patch.

Run "TZ=UTC0 admin/update-copyright".

Although static_assert is C11-specific, and Emacs remains on C99, it
has been backported to older compilers by Gnulib.  Gnulib has already
changed to prefer static_assert, and we can do the same.

* lib-src/asset-directory-tool.c (main_2):
* src/alloc.c (BLOCK_ALIGN, aligned_alloc, lisp_align_malloc)
(vectorlike_nbytes, allocate_pseudovector):
* src/android.c (android_globalize_reference, android_set_dashes):
* src/android.h:
* src/androidfont.c (androidfont_draw, androidfont_text_extents):
* src/androidvfs.c:
* src/bidi.c (BIDI_CACHE_MAX_ELTS_PER_SLOT, bidi_find_bracket_pairs):
* src/buffer.c (init_buffer_once):
* src/casefiddle.c (do_casify_multibyte_string):
* src/dispnew.c (scrolling_window, scrolling):
* src/editfns.c (styled_format):
* src/emacs-module.c (module_extract_big_integer):
* src/fileio.c (Fdo_auto_save):
* src/fns.c (next_almost_prime, hash_string):
* src/fringe.c (init_fringe):
* src/keyboard.h (kbd_buffer_store_event_hold):
* src/keymap.c:
* src/lisp.h (memclear, reduce_emacs_uint_to_hash_hash, modiff_incr):
* src/lread.c (skip_lazy_string):
* src/pdumper.c (dump_bignum, Fdump_emacs_portable)
(dump_do_dump_relocation, pdumper_load):
* src/process.c (make_process, Fmake_process, connect_network_socket):
* src/regex-emacs.c:
* src/sort.c (tim_sort):
* src/sysdep.c (init_random, SSIZE_MAX):
* src/thread.c:
* src/timefns.c (trillion_factor):
* src/unexelf.c:
* src/xterm.c (x_send_scroll_bar_event): Prefer static_assert to Gnulib
verify.  Remove import of verify.h, except when used for other reasons.

* doc/lispref/variables.texi (Intro to Buffer-Local): Fix typo
in documentation.

* src/data.c (KBOARD_OBJFWDP): Move to lisp.h.
(kboard_for_bindings): New variable.
(do_symval_forwarding, store_symval_forwarding): Call
kboard_for_bindings rather than retrieving this value directly.
(set_default_internal): New argument WHERE; if valcontents be a
Lisp_Kboard_Objfwd and WHERE be specified, save the binding
there.  All callers changed.

* src/eval.c (specpdl_where): Adjust for changes in structure
layout.
(specpdl_kboard): New function.
(do_specbind): Clear let->where.kbd in ordinary SPECPDL_LETs,
and set it to the kboard where the binding will be installed if
binding keyboard forwards.
(specbind, do_one_unbind, specpdl_unrewind): Provide
specpdl_kboard in invocation of set_default_internal.

* src/keyboard.c (delete_kboard): Clean thread specpdls of
references to kboards.

* src/keyboard.h (KBOARD_OBJFWDP): Move from data.c.

* src/lisp.h (union specbinding) <let.where>: Convert into
union of KBOARD and Lisp_Object.

* src/thread.c (all_threads): Export.

* src/thread.h: Adjust correspondingly.

Much like the NS port, only the main thread receives input from
the user interface, which is fortunately not a major problem for
packages such as lsp-mode that create Lisp threads.

* configure.ac: Enable with_threads under Android.

* src/android.c (android_init_events): Set `main_thread_id' to
the ID of the main thread.
(setEmacsParams): Set new global variable `android_jvm' to the
JVM object, for the purpose of attaching Lisp threads to the
JVM.
(android_select): [THREADS_ENABLED]: If the caller isn't the
main thread, resort to pselect.  Don't check query before select
returns.
(android_check_query): Export.

* src/android.h (_ANDROID_H_): Define new macro and update
prototypes.

* src/process.c (android_select_wrapper): New function.
(wait_reading_process_output): If THREADS_ENABLED, call
thread_select through the Android select wrapper.

* src/thread.c (post_acquire_global_lock): Call
android_check_query; replace android_java_env with the incoming
Lisp thread's.
(run_thread): Attach and detach the thread created to the JVM.
(init_threads): Set the main thread's JNI environment object.

* src/thread.h (struct thread_state) <java_env>: New field.

This is the function that marks the C stack.  Avoid confusion with the
new mark stack, a stack used in the GC mark phase.

* src/alloc.c (SETJMP_WILL_LIKELY_WORK, SETJMP_WILL_NOT_WORK)
(mark_stack, mark_c_stack):
* src/lisp.h:
* src/thread.c (mark_one_thread): Rename mark_stack to mark_c_stack.

Use a dedicated stack for bytecode, instead of using the C stack.
Stack frames are managed explicitly and we stay in the same
exec_byte_code activation throughout bytecode function calls and
returns.  In other words, exec_byte_code no longer uses recursion
for calling bytecode functions.

This results in better performance, and bytecode recursion is no
longer limited by the size of the C stack.  The bytecode stack is
currently of fixed size but overflow is handled gracefully by
signalling a Lisp error instead of the hard crash that we get now.

In addition, GC marking of the stack is now faster and more precise.
Full precision could be attained if desired.

* src/alloc.c (ATTRIBUTE_NO_SANITIZE_ADDRESS): Make non-static.
* src/bytecode.c (enum stack_frame_index, BC_STACK_SIZE)
(sf_get_ptr, sf_set_ptr, sf_get_lisp_ptr, sf_set_lisp_ptr)
(sf_get_saved_pc, sf_set_saved_pc, init_bc_thread, free_bc_thread)
(mark_bytecode, Finternal_stack_stats, valid_sp): New.
(exec_byte_code): Adapt to use the new bytecode stack.
(syms_of_bytecode): Add defsubr.
* src/eval.c (unwind_to_catch): Restore saved stack frame.
(push_handler_nosignal): Save stack frame.
* src/lisp.h (struct handler): Add act_rec member.
(get_act_rec, set_act_rec): New.
* src/thread.c (mark_one_thread): Call mark_bytecode.
(finalize_one_thread): Free bytecode thread state.
(Fmake_thread, init_threads): Set up bytecode thread state.
* src/thread.h (struct bc_thread_state): New.
(struct thread_state): Add bytecode thread state.