Ubuntu/Debian Firefox packages are built without SIMD

[Mateusz Mikuła]

Official Firefox releases and other distributions packages are built with `--enable-rust-simd` to improve performance. Official build option: https://github.com/mozilla/gecko-dev/blob/13788edbabb04d004e4a1ceff41d4de68a8320a2/build/mozconfig.rust#L12

`--enable-rust-simd` enables runtime detection of CPU features such as SSE and AVX in Rust written components.

To check if Firefox is built with simd open `about:buildconfig` and look for `--enable-rust-simd`.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Launchpad Janitor (janitor)]

This bug was fixed in the package firefox - 65.0+build2-0ubuntu1

---------------
firefox (65.0+build2-0ubuntu1) disco; urgency=medium

  * New upstream stable release (65.0build2)

  [ Olivier Tilloy ]
  * Fix build with newer versions of cargo, which ignore local configuration
    (see https://github.com/rust-lang/cargo/issues/6397)
    - update debian/build/rules.mk
  * Re-enable and update debian/patches/unity-menubar.patch

  [ Rico Tzschichholz ]
  * Drop upstreamed patches
    - remove debian/patches/fix-pixman-build-ppc64el.patch
    - remove debian/patches/extra-webrtc-build-configs.patch
    - remove debian/patches/update-gn-mozbuild.patch
  * Update patches
    - debian/patches/rust-drop-dll-checksums.patch
    - debian/patches/webrtc-fix-compiler-flags-for-armhf.patch
    - debian/patches/fix-armhf-webrtc-build.patch
    - debian/patches/no-region-overrides-for-google-search.patch
    - debian/patches/ppc-no-static-sizes.patch
    - debian/patches/ubuntu-ua-string-changes.patch
  * Bump build-dep on rustc >= 1.30.0 and cargo >= 0.31
  * Use amazon-in override for "gu-IN", "mai", "ml", "pa-IN", "ta"
    - update debian/config/searchplugins.conf
  * Revert parts of google search update
    - add debian/patches/partially-revert-google-search-update.patch
  * Build with --enable-rust-simd (LP: #1808980) (except on i386 and armhf)
    - update debian/config/mozconfig.in
  * Update cbindgen to 0.6.8
    - debian/build/create-tarball.py

 -- Olivier Tilloy <email address hidden> Mon, 28 Jan 2019 14:17:13 +0100