tce-load -i compiletc gperf gst-plugins-base-dev gst-plugins-base-gir gtk3-dev gtk3-gir libsecret-dev libsecret-gir libsoup-dev libsoup-gir libwebp-dev ruby-dev gudev-lib-dev harfbuzz-icu-dev libxslt-dev perl5 gobject-introspection-dev intltool gsettings-desktop-schemas-dev geoclue-dev enchant-dev hicolor-icon-theme gtk2-dev python

cd /usr/bin
sudo ln -s ../local/bin/gcc gcc
sudo ln -s ../local/bin/cc cc

cd webkitgtk-2.4.11

patch -Np1 -i ../webkitgtk-2.4.11-gcc6-1.patch
patch -Np1 -i ../webkitgtk-2.4.11-icu.patch

sed -i '/generate-gtkdoc --rebase/s:^:# :' GNUmakefile.in

mkdir build-3
cd build-3

CFLAGS="-fno-delete-null-pointer-checks -Wno-expansion-to-defined" CXXFLAGS="-fno-delete-null-pointer-checks -Wno-expansion-to-defined" CC="gcc -mtune=generic -Os -pipe" CXX="g++ -mtune=generic -Os -pipe -D_GLIBCXX_USE_C99_MATH" ../configure --prefix=/usr/local --disable-static --libexecdir=/usr/local/lib/webkit2gtk-3.0 --enable-introspection

[lto fails]

find . -name GNUmakefile -type f -exec sed -i 's/-O2//g' {} \;

time make -j5 [1h 28m 39s]
sudo make install

WebKit was configured with the following options:

Build configuration:
 Enable debugging (slow)                                  : no
 Compile with debug symbols (slow)                        : no
 Enable GCC build optimization                            : yes
 Code coverage support                                    : no
 Optimized memory allocator                               : yes
 Accelerated rendering backend                            : OpenGL (gl, egl, glx)
 Geolocation backend                                      : Geoclue 2

Features:
=======
 WebKit1 support                                          : yes
 WebKit2 support                                          : yes
 Accelerated Compositing                                  : yes
 Accelerated 2D canvas                                    : no
 Battery API support                                      : no
 Gamepad support                                          : no
 Geolocation support                                      : yes
 HTML5 video element support                              : yes
 JIT compilation                                          : auto
 FTL JIT compilation                                      : no
 Opcode stats                                             : no
 SVG fonts support                                        : yes
 SVG support                                              : yes
 Spellcheck support                                       : yes
 Credential storage support                               : yes
 Web Audio support                                        : yes
 WebGL                                                    : yes


GTK+ configuration:
 GTK+ version                                             : 3.0
 GDK targets                                              : x11, wayland
 Introspection support                                    : yes
 Generate documentation                                   : no