tce-load -i compiletc qt-5.x-dev libxslt-dev ruby-dev gperf 

cd qtwebkit-opensource-src-5.9.0

patch -Np1 -i ../qtwebkit-5.9.0-icu_59-1.patch

sed -e '/CONFIG/a QMAKE_CXXFLAGS += -Wno-expansion-to-defined' -i Tools/qmake/mkspecs/features/unix/default_pre.prf

mkdir build
cd build

qmake ../WebKit.pro

make CC="gcc -flto -fuse-linker-plugin -mtune=generic -Os -pipe" CXX="g++ -flto -fuse-linker-plugin -mtune=generic -Os -pipe" [1h 31m 18s]

make install

sudo find /usr/local/lib/ -name \*.prl -exec sed -i -e '/^QMAKE_PRL_BUILD_DIR/d' {} \;

Final configuration:

Build ......................... webkit1 webkit2
Configuration ................. release
All-in-one files .............. no
GNUmake ....................... yes
Static libs as shared ......... no
Static libs as thin archives .. yes
Production build .............. yes

Have .......................... qtquick qtprintsupport qstyle qttestlib qtpositioning qtsensors xcomposite xrender glx fontconfig sqlite3
Use ........................... tiled_backing_store cross_platform_context_menus libxml2 zlib webp libjpeg libpng plugin_backend_xlib 3d_graphics gstreamer native_fullscreen_video graphics_surface glx leveldb glib
Features ...................... fast_mobile_scrolling gesture_events inspector_server legacy_viewport_adaption smooth_scrolling subpixel_layout touch_adjustment view_mode_css_media plugin_architecture_x11 plugin_process

3D Rendering .................. yes
Accelerated 2D Canvas ......... yes
Battery Status ................ no
Blob .......................... yes
Canvas Path ................... yes
CanvasProxy ................... no
Channel Messaging ............. yes
Content Security Policy 1.1 ... no
CSS Device Adaptation ......... no
CSS Exclusions ................ yes
CSS Shapes .................... yes
CSS Filters ................... yes
CSS3 Conditional Rules support (i.e. @supports)  no
CSS3 Text ..................... no
CSS3 Text Line Break .......... no
CSS box-decoration-break ...... yes
CSS image-orientation ......... no
CSS image-resolution .......... no
CSS image-set ................. yes
CSS Regions ................... yes
CSS Shaders ................... no
CSS sticky position ........... yes
CSS Compositing ............... yes
Support for unprefixed CSS animations and transforms  yes
CSS Variable .................. no
Custom Scheme Handler ......... no
Datalist Element .............. yes
Data Transfer Items ........... no
Details Element ............... yes
Device Orientation ............ yes
Dialog Element ................ no
Directory Upload .............. no
Expose DOM4 Events constructors  no
Download Attribute ............ yes
File System ................... no
Filters ....................... yes
Font Load Events .............. no
FTP Directory ................. yes
Fullscreen API ................ yes
Gamepad ....................... yes
Geolocation ................... yes
High DPI Canvas ............... no
Icondatabase .................. yes
Iframe seamless attribute ..... yes
Indexed Database .............. yes
Input Speech .................. no
Input Type Color .............. yes
Input Type Date ............... no
Broken Input Type Datetime .... no
Input Type Datetimelocal ...... no
Input Type Month .............. no
Input Type Time ............... no
Input Type Week ............... no
Inspector ..................... yes
JavaScript Debugger ........... yes
Legacy Notifications .......... yes
Legacy Vendor Prefix .......... yes
Legacy Web Audio .............. yes
Link Prefetch ................. yes
MathML ........................ no
Media Capture ................. no
Media Source .................. no
Media Statistics .............. no
Media Stream .................. no
Meter Element ................. yes
MHTML ......................... yes
Microdata ..................... no
Scaled mouse cursor ........... no
Navigator Content Utils ....... no
Netscape Plugin API ........... yes
Network Info .................. no
Support for 'X-Content-Type-Options: nosniff'  no
Notifications ................. yes
Orientation Events ............ yes
Page Visibility API ........... yes
Performance Timeline .......... no
Progress Element .............. yes
Proximity Events .............. no
Quota ......................... no
Resolution media query ........ yes
Resource Timing ............... no
Request Animation Frame ....... yes
Seccomp Filter sandbox ........ no
Scripted Speech ............... no
Shadow DOM .................... no
Shared Workers ................ yes
SQL Database .................. yes
Style Scoped .................. no
Suid sandbox for linux ........ no
SVG ........................... yes
SVG Fonts ..................... yes
HTMLTemplateElement ........... no
Text Autosizing ............... no
Tiled Backing Store ........... no
Threaded HTML parser .......... no
Touch Events .................. yes
Touch Slider .................. yes
Touch Icon Loading Support .... no
User Timing ................... no
Vibration ..................... no
Video ......................... yes
Video Track ................... yes
WebGL ......................... yes
Web Audio ..................... no
Web Sockets ................... yes
Web Timing .................... yes
Workers ....................... yes
XHR Timeout ................... yes
XSLT .......................... yes