Bug: https://bugs.gentoo.org/598928

--- a/source.txt
+++ b/source.txt
@@ -13400,13 +13400,13 @@
 
 BRANCH MAIN
 {
-    symbol	'\\207'
+    symbol	static_cast<u8>('\\207')
     welcome	"%U <return> to the main dungeon."
 }
 
 BRANCH TRIDUDE
 {
-    symbol	'\\211'
+    symbol	static_cast<u8>('\\211')
     welcome	"%U <enter> a cave made of metal."
 }