- Correct plugin directory for aarch64 (boo#1061207). The wrapper
script was not detecting aarch64 as a 64 bit architecture, thus
used /usr/lib/browser-plugins/.
- Drop libgnomeui-devel, and replace it with pkgconfig(gconf-2.0),
pkgconfig(gtk+-2.0), pkgconfig(gtk+-unix-print-2.0),
pkgconfig(glib-2.0), pkgconfig(gobject-2.0) and
pkgconfig(gdk-x11-2.0) BuildRequires, align with what configure
looks for.

- update to Firefox 56.0 (boo#1060445)
* Firefox Screenshots
* Find Options/Preferences more quickly with new search function
* Media is no longer auto-played when opened in a background tab
* Enable CSS Grid Layout View
MFSA 2017-21
* CVE-2017-7793 (bmo#1371889)
Use-after-free with Fetch API
* CVE-2017-7817 (bmo#1356596) (Android-only)
Firefox for Android address bar spoofing through fullscreen mode
* CVE-2017-7818 (bmo#1363723)
Use-after-free during ARIA array manipulation
* CVE-2017-7819 (bmo#1380292)
Use-after-free while resizing images in design mode
* CVE-2017-7824 (bmo#1398381)
Buffer overflow when drawing and validating elements with ANGLE
* CVE-2017-7805 (bmo#1377618) (fixed via NSS requirement)
Use-after-free in TLS 1.2 generating handshake hashes
* CVE-2017-7812 (bmo#1379842)
Drag and drop of malicious page content to the tab bar can open locally stored files
* CVE-2017-7814 (bmo#1376036)