Generate upcase and downcase tables from Unicode data (bug#24603)

Use Unicode data to generate case tables instead of mostly repeating
them in lisp code.  Do that in a way which maps ‘Dz’ (and similar)
digraph to ‘dz’ when down- and ‘DZ’ when upcasing.

https://debbugs.gnu.org/cgi/bugreport.cgi?msg=89;bug=24603 lists all
changes to syntax table and case tables introduced by this commit.

* lisp/international/characters.el: Remove case-pairs defined with
explicit Lisp code and instead use Unicode character properties.

* test/src/casefiddle-tests.el (casefiddle-tests--characters,
casefiddle-tests-casing): Update test cases which are now working
as they should.

1 files changed, 3 insertions, 4 deletions

diff --git a/test/src/casefiddle-tests.el b/test/src/casefiddle-tests.el
index 8d9cf34ee50..c752bb09172 100644
--- a/test/src/casefiddle-tests.el
+++ b/test/src/casefiddle-tests.el
@@ -73,8 +73,7 @@
 
     (?Σ ?Σ ?σ ?Σ)
     (?σ ?Σ ?σ ?Σ)
-    ;; FIXME(bug#24603): Another broken one:
-    ;;(?ς ?Σ ?ς ?Σ)
+    (?ς ?Σ ?ς ?Σ)
 
     (?Ⅷ ?Ⅷ ?ⅷ ?Ⅷ)
     (?ⅷ ?Ⅷ ?ⅷ ?Ⅷ)))
@@ -196,7 +195,6 @@
         ;;("fish" "FIsh" "fish" "Fish" "Fish")
         ;;("Straße" "STRASSE" "straße" "Straße" "Straße")
         ;;("ΌΣΟΣ" "ΌΣΟΣ" "όσος" "Όσος" "Όσος")
-        ;;("όσος" "ΌΣΟΣ" "όσος" "Όσος" "Όσος")
         ;; And here’s what is actually happening:
         ("DŽUNGLA" "DŽUNGLA" "džungla" "DŽungla" "DŽUNGLA")
         ("Džungla" "DžUNGLA" "džungla" "Džungla" "Džungla")
@@ -205,7 +203,8 @@
         ("fish" "fiSH" "fish" "fish" "fish")
         ("Straße" "STRAßE" "straße" "Straße" "Straße")
         ("ΌΣΟΣ" "ΌΣΟΣ" "όσοσ" "Όσοσ" "ΌΣΟΣ")
-        ("όσος" "ΌΣΟς" "όσος" "Όσος" "Όσος"))))))
+
+        ("όσος" "ΌΣΟΣ" "όσος" "Όσος" "Όσος"))))))
 
 (ert-deftest casefiddle-tests-casing-byte8 ()
   (should-not