- add fix-build-after-y2038-changes-in-glibc.patch

- Generate langpacks sequentially to avoid file corruption
from racy file writes (boo#1137970)

- Mozilla Firefox 68.0
* Dark mode in reader view
* Improved extension security and discovery
* Cryptomining and fingerprinting protections are added to strict
content blocking settings in Privacy & Security preferences
* Camera and microphone access now require an HTTPS connection
MFSA 2019-21 (bsc#1140868)
* CVE-2019-9811 (bmo#1538007, bmo#1539598, bmo#1563327)
Sandbox escape via installation of malicious languagepack
* CVE-2019-11711 (bmo#1552541)
Script injection within domain through inner window reuse
* CVE-2019-11712 (bmo#1543804)
Cross-origin POST requests can be made with NPAPI plugins by
following 308 redirects
* CVE-2019-11713 (bmo#1528481)
Use-after-free with HTTP/2 cached stream
* CVE-2019-11714 (bmo#1542593)
NeckoChild can trigger crash when accessed off of main thread
* CVE-2019-11729 (bmo#1515342)
Empty or malformed p256-ECDH public keys may trigger a segmentation fault
* CVE-2019-11715 (bmo#1555523)
HTML parsing error can contribute to content XSS
* CVE-2019-11716 (bmo#1552632)
globalThis not enumerable until accessed
* CVE-2019-11717 (bmo#1548306)