tce-load -i itstool docbook_xsl libxslt-dev

cd gtk-doc-1.19

CC="gcc -flto -fuse-linker-plugin -mtune=generic -Os -pipe" CXX="g++ -flto -fuse-linker-plugin -mtune=generic -Os -pipe -fno-exceptions -fno-rtti" ./configure --prefix=/usr/local --with-xml-catalog=/usr/local/etc/xml/catalog

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

make
sudo make install

gtk-doc was configured with the following options:
==================================================
configure: ** Python based tools enabled, using /usr/local/bin/python
configure:    SGML support disabled, no jade processor available
configure:    XML PDF support disabled, no dblatex or fop available
configure:    Syntax highlighting of examples disabled
configure: ** Building regression tests
configure:    Debug tracing disabled
configure:    Debug tracing disabled
configure: ** Documentation enabled