This differential patches SQLCipher amalgamation to enable sqlite 3 session extension usage and to enfore XCode to use `sqlite3.h` header from SQLCipher
amalgamation instead of `sqlite3.h` provided by the system.
I don't plan to land this diff, but to make a release of `SQLCipher-amalgamation` updated with changes in this diff.
Adding @ashoat as reviewer since it affects project dependencies.