diff --git a/gnu/packages/games.scm b/gnu/packages/games.scm
index 0b4f8c6bfe..1e5f0a1e9a 100644
--- a/gnu/packages/games.scm
+++ b/gnu/packages/games.scm
@@ -4497,6 +4497,7 @@ (define-public openttd
      `(("opengfx" ,openttd-opengfx)
        ("openmsx" ,openttd-openmsx)
        ("opensfx" ,openttd-opensfx)
+       ("gcc" ,gcc-9)                   ; for #include <charconv>
        ,@(package-native-inputs openttd-engine)))))
 
 (define openrct2-title-sequences