Add support for the Tagalog script

* lisp/language/philippine.el ("Tagalog"): New language environment.
Add composition rules for Tagalog.  Add sample text and input
method.
* lisp/international/fontset.el (script-representative-chars)
(setup-default-fontset): Support Tagalog.
* lisp/leim/quail/philippine.el ("tagalog"): New input method.
* lisp/loadup.el: Preload lisp/language/philippine.el.

* etc/HELLO: Add a Tagalog greeting.
* etc/NEWS: Announce the new language environment and its
input method.
(Bug#55529)

etc/HELLO

@@ -90,6 +90,7 @@ Swedish (svenska)	Hej / Goddag / Hallå
 Syloti Nagri (ꠍꠤꠟꠐꠤ ꠘꠣꠉꠞꠤ)	ꠀꠌ꠆ꠍꠣꠟꠣꠝꠥ ꠀꠟꠣꠁꠇꠥꠝ / ꠘꠝꠡ꠆ꠇꠣꠞ
 Tamil (தமிழ்)	வணக்கம்
 Telugu (తెలుగు)	నమస్కారం
+Tagalog (ᜊᜌ᜔ᜊᜌᜒᜈ᜔)	ᜃᜓᜋᜓᜐ᜔ᜆ
 TaiViet (ꪁꪫꪱꪣ ꪼꪕ)	ꪅꪰꪙꫂ ꪨꪮꫂ ꪁꪫꪱ / ꪅꪽ ꪨꪷ ꪁꪫꪱ
 Thai (ภาษาไทย)	สวัสดีครับ / สวัสดีค่ะ
 Tibetan (བོད་སྐད་)	བཀྲ་ཤིས་བདེ་ལེགས༎

etc/NEWS

@@ -810,6 +810,7 @@ corresponding language environments are:
 **** Siddham script and language environment
 **** Syloti Nagri script and language environment
 **** Modi script and language environment
+**** Baybayin script and Tagalog language environment
 
 ---
 *** The "Oriya" language environment was renamed to "Odia".

lisp/international/fontset.el

@@ -182,6 +182,7 @@
 	(canadian-aboriginal #x14C0)
 	(ogham #x168F)
 	(runic #x16A0)
+        (tagalog #x1700)
 	(khmer #x1780)
 	(mongolian #x1826)
         (tai-le #x1950)
@@ -748,6 +749,7 @@
                     cham
 		    ogham
 		    runic
+                    tagalog
 		    symbol
 		    braille
 		    yi

lisp/language/philippine.el

@@ -0,0 +1,59 @@
+;;; philippine.el --- Philippine languages support  -*- coding: utf-8; lexical-binding: t; -*-
+
+;; Copyright (C) 2022 Free Software Foundation, Inc.
+
+;; Author: समीर सिंह Sameer Singh <lumarzeli30@gmail.com>
+;; Keywords: multilingual, input method, i18n, Philippines
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This file contains definitions of Philippine language environments, and
+;; setups for displaying the scripts used there.
+
+;;; Code:
+
+(set-language-info-alist
+ "Tagalog" '((charset unicode)
+             (coding-system utf-8)
+             (coding-priority utf-8)
+             (input-method . "tagalog")
+             (sample-text . "Tagalog (ᜊᜌ᜔ᜊᜌᜒᜈ᜔)	ᜃᜓᜋᜓᜐ᜔ᜆ")
+             (documentation . "\
+Tagalog which uses the Baybayin script is supported in
+this language environment.")))
+
+;; Tagalog composition rules
+(let ((akshara              "[\x1700-\x1711\x171F]")
+      (vowel                "[\x1712\x1713]")
+      (virama               "\x1714")
+      (pamudpod             "\x1715"))
+  (set-char-table-range composition-function-table
+                        '(#x1714 . #x1714)
+                        (list (vector
+                               ;; Akshara virama syllables
+                               (concat akshara virama vowel "?")
+                               1 'font-shape-gstring)))
+  (set-char-table-range composition-function-table
+                        '(#x1715 . #x1715)
+                        (list (vector
+                               ;; Akshara pamudpod syllables
+                               (concat akshara pamudpod vowel "?")
+                               1 'font-shape-gstring))))
+
+(provide 'philippine)
+;;; philippine.el ends here

lisp/leim/quail/philippine.el

@@ -0,0 +1,65 @@
+;;; philippine.el --- Quail package for inputting Philippine characters  -*- lexical-binding: t; -*-
+
+;; Copyright (C) 2022 Free Software Foundation, Inc.
+
+;; Author: समीर सिंह Sameer Singh <lumarzeli30@gmail.com>
+;; Keywords: multilingual, input method, i18n, Philippines
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This input method supports scripts like Tagalog, Hanunoo, Buhid and
+;; Tagbanwa.
+
+;;; Code:
+
+(require 'quail)
+
+(quail-define-package
+ "tagalog" "Tagalog" "ᜊ" nil "Baybayin phonetic input method."
+ nil t t t t nil nil nil nil nil t)
+
+(quail-define-rules
+ ("q"  ?₱)
+ ("w"  ?ᜏ)
+ ("r"  ?ᜍ)
+ ("R"  ?ᜟ)
+ ("t"  ?ᜆ)
+ ("y"  ?ᜌ)
+ ("u"  ?ᜓ)
+ ("U"  ?ᜂ)
+ ("i"  ?ᜒ)
+ ("I"  ?ᜁ)
+ ("p"  ?ᜉ)
+ ("a"  ?ᜀ)
+ ("s"  ?ᜐ)
+ ("d"  ?ᜇ)
+ ("f"  ?᜔)
+ ("g"  ?ᜄ)
+ ("h"  ?ᜑ)
+ ("j"  ?᜵)
+ ("J"  ?᜶)
+ ("k"  ?ᜃ)
+ ("l"  ?ᜎ)
+ ("v"  ?᜕)
+ ("b"  ?ᜊ)
+ ("n"  ?ᜈ)
+ ("N"  ?ᜅ)
+ ("m"  ?ᜋ))
+
+(provide 'philippine)
+;;; philippine.el ends here

lisp/loadup.el

@@ -245,6 +245,7 @@
 (load "language/khmer")
 (load "language/burmese")
 (load "language/cham")
+(load "language/philippine")
 
 (load "indent")
 (let ((max-specpdl-size (max max-specpdl-size 1800)))