Regressed by https://github.com/unicode-org/icu/commit/c3fe7e09d844

GSCharacterPanel.m:81:10: error: use of undeclared identifier 'TRUE'
  return TRUE;
         ^
GSCharacterPanel.m:106:10: error: use of undeclared identifier 'TRUE'
  return TRUE;
         ^

--- Source/GSCharacterPanel.m.orig	2019-01-06 22:00:38 UTC
+++ Source/GSCharacterPanel.m
@@ -78,7 +78,7 @@
 static UBool enumCharNamesFn(void *context, UChar32 code, UCharNameChoice nameChoice, const char *name, int32_t length)
 {
   [(NSMutableIndexSet*)context addIndex: (NSUInteger)code];
-  return TRUE;
+  return true;
 }
 
 static NSIndexSet *AssignedCodepoints()
@@ -103,7 +103,7 @@ static UBool searchCharNamesFn(void *context, UChar32 
     {
       [ctx->set addIndex: (NSUInteger)code];
     }
-  return TRUE;
+  return true;
 }
 
 static NSIndexSet *CodepointsWithNameContainingSubstring(NSString *str)