Log Message:
firefox68: Update to 68.3.0

pkgsrc changes:

- Fixed building with wayland libs installed

Security fixes:

- CVE-2019-17008: Use-after-free in worker destruction
- CVE-2019-13722: Stack corruption due to incorrect number of arguments in \ 
WebRTC code
- CVE-2019-11745: Out of bounds write in NSS when encrypting with a block cipher
- CVE-2019-17009: Updater temporary files accessible to unprivileged processes
- CVE-2019-17010: Use-after-free when performing device orientation checks
- CVE-2019-17005: Buffer overflow in plain text serializer
- CVE-2019-17011: Use-after-free when retrieving a document in antitracking
- CVE-2019-17012: Memory safety bugs fixed in Firefox 71 and Firefox ESR 68.3