[4.2] Remove final from ICU4C UnicodeSet class

This fixes a warning in Clang: -Wunnecessary-virtual-specifier

Author: aaronfranke

thirdparty/README.md

@@ -382,6 +382,8 @@ Files generated from upstream source:
 4. Delete `data/out` folder and rebuild data: `cd data && rm -rf ./out && make`
 5. Copy `source/data/out/icudt73l.dat` to the `{GODOT_SOURCE}/thirdparty/icu4c/icudt73l.dat`
 
+Apply `patches` to fix the `-Wunnecessary-virtual-specifier` warning in Clang. Newer versions of ICU4C do not have this warning, this only applies to older versions.
+
 
 ## jpeg-compressor
 

thirdparty/icu4c/common/unicode/uniset.h

@@ -282,7 +282,7 @@ class RuleCharacterIterator;
  * @author Alan Liu
  * @stable ICU 2.0
  */
-class U_COMMON_API UnicodeSet final : public UnicodeFilter {
+class U_COMMON_API UnicodeSet : public UnicodeFilter {
 private:
     /**
      * Enough for sets with few ranges.

thirdparty/icu4c/patches/icu4c_remove_final_unicode_set.patch

@@ -0,0 +1,13 @@
+diff --git a/thirdparty/icu4c/common/unicode/uniset.h b/thirdparty/icu4c/common/unicode/uniset.h
+index 127e4ce..f68e714 100644
+--- a/thirdparty/icu4c/common/unicode/uniset.h
++++ b/thirdparty/icu4c/common/unicode/uniset.h
+@@ -282,7 +282,7 @@ class RuleCharacterIterator;
+  * @author Alan Liu
+  * @stable ICU 2.0
+  */
+-class U_COMMON_API UnicodeSet final : public UnicodeFilter {
++class U_COMMON_API UnicodeSet : public UnicodeFilter {
+ private:
+     /**
+      * Enough for sets with few ranges.