Support for Unicode emoji sequences

This covers both sequences using Zero-Width-Joiner codepoints and
those without. Bug#39799, I hope.

* .gitignore: Add emoji-zwj.el
* admin/notes/unicode: Add emoji-zwj-sequences.txt and
emoji-sequences.txt references.  Describe how to test after updating
to a newer Unicode version.
* admin/unidata/Makefile.in (all): add emoji-zwj.el as a dependency.
(emoji-zwj.el): Add target plus rules for building.
(gen-clean): Add emoji-zwj.el.
* admin/unidata/README: Add emoji-zwj-sequences.txt and
emoji-sequences.txt references.
* admin/unidata/blocks.awk: Force emoji script to be used for certain
codepoints that are used by the Unicode sequences.
* admin/unidata/emoji-sequences.txt: New file.
* admin/unidata/emoji-zwj-sequences.txt: New file.
* admin/unidata/emoji-zwj.awk: New file.  Derives
composition-function-table rules from emoji-zwj-sequences.txt, plus
hardcodes some derived manually from emoji-sequences.txt.
* etc/NEWS: Announce change.
* lisp/international/characters.el: Load the generated emoji-zwj.el
* src/Makefile.in (emoji-zwj): New target.
(temacs): Add emoji-zwj as a dependency.

1 files changed, 6 insertions, 2 deletions

diff --git a/src/Makefile.in b/src/Makefile.in
index bb69a657077..c11d96d2c4e 100644
--- a/src/Makefile.in
+++ b/src/Makefile.in
@@ -545,7 +545,11 @@ charscript = ${lispintdir}/charscript.el
 ${charscript}: FORCE
         $(MAKE) -C ../admin/unidata $(notdir $@)
 
-${lispintdir}/characters.elc: ${charscript:.el=.elc}
+emoji-zwj = ${lispintdir}/emoji-zwj.el
+${emoji-zwj}: FORCE
+        $(MAKE) -C ../admin/unidata $(notdir $@)
+
+${lispintdir}/characters.elc: ${charscript:.el=.elc} ${emoji-zwj:.el=.elc}
 
 SYSTEM_TYPE = @SYSTEM_TYPE@
 
@@ -634,7 +638,7 @@ endif
 ## This goes on to affect various things, and the emacs binary fails
 ## to start if Vinstallation_directory has the wrong value.
 temacs$(EXEEXT): $(LIBXMENU) $(ALLOBJS) $(LIBEGNU_ARCHIVE) $(EMACSRES) \
-  $(charsets) $(charscript) $(MAKE_PDUMPER_FINGERPRINT)
+  $(charsets) $(charscript) ${emoji-zwj} $(MAKE_PDUMPER_FINGERPRINT)
         $(AM_V_CCLD)$(CC) -o $@.tmp \
           $(ALL_CFLAGS) $(TEMACS_LDFLAGS) $(LDFLAGS) \
           $(ALLOBJS) $(LIBEGNU_ARCHIVE) $(W32_RES_LINK) $(LIBES)