Update pkg-config/READMD.md

pkg-config/READMD.md

@@ -1,6 +1,18 @@
 ## `pkg-config`
 
 ```sh
+sudo apt install -y gnome-themes-extra gtk2-engines-murrine \
+    gtk2-engines-pixbuf adwaita-icon-theme-full
+
+mkdir -p ~/.config/gtk-3.0
+tee -a ~/.config/gtk-3.0/settings.ini << 'EOF'
+[Settings]
+gtk-application-prefer-dark-theme=1
+gtk-theme-name=Adwaita-dark
+EOF
+echo 'export GTK_THEME=Adwaita:dark' >> ~/.bashrc
+source ~/.bashrc
+
 sudo apt install -y libgtk-3-dev build-essential pkg-config
 pkg-config --cflags --libs gtk+-3.0