diff --git a/pkgs/servers/sql/mariadb/default.nix b/pkgs/servers/sql/mariadb/default.nix
index f183a1fb12b5..7501dab6a1bb 100644
--- a/pkgs/servers/sql/mariadb/default.nix
+++ b/pkgs/servers/sql/mariadb/default.nix
@@ -47,6 +47,10 @@ common = rec { # attributes common to both builds
 
   prePatch = ''
     sed -i 's,[^"]*/var/log,/var/log,g' storage/mroonga/vendor/groonga/CMakeLists.txt
+    # libc++abi 11 uses `#include <version>`, include paths often include
+    # project dirs and that means files with version numbers get included as if
+    # they were a header. This includes files name `VERSION` on
+    # case-insensitive file systems.
     sed -i 's,/version\>,/version_full,' storage/mroonga/CMakeLists.txt
     mv storage/mroonga/version storage/mroonga/version_full
     sed -i 's,/VERSION\>,/VERSION_FULL,' cmake/mysql_version.cmake