Copied from Fedora.

https://bugzilla.redhat.com/show_bug.cgi?id=1189303
http://pkgs.fedoraproject.org/cgit/webkitgtk.git/commit/?id=e689e45d0cc2c50484e69d20371ba607af7326f3

diff -up webkitgtk-2.4.9/Source/WebCore/platform/sql/SQLiteStatement.cpp.sql_initialize_string webkitgtk-2.4.9/Source/WebCore/platform/sql/SQLiteStatement.cpp
--- webkitgtk-2.4.9/Source/WebCore/platform/sql/SQLiteStatement.cpp.sql_initialize_string	2015-09-14 09:25:43.004200172 +0200
+++ webkitgtk-2.4.9/Source/WebCore/platform/sql/SQLiteStatement.cpp	2015-09-14 09:25:57.852082368 +0200
@@ -71,7 +71,7 @@ int SQLiteStatement::prepare()
     // this lets SQLite avoid an extra string copy.
     size_t lengthIncludingNullCharacter = query.length() + 1;
 
-    const char* tail;
+    const char* tail = nullptr;
     int error = sqlite3_prepare_v2(m_database.sqlite3Handle(), query.data(), lengthIncludingNullCharacter, &m_statement, &tail);
 
     if (error != SQLITE_OK)