tce-load -i compiletc cmake gobject-introspection-dev icu62-dev vala-dev perl5 libxml2-dev 

cd libical-3.0.4

mkdir build
cd build

cmake -LAH -DCMAKE_C_FLAGS_RELEASE="-flto -fuse-linker-plugin -march=i486 -mtune=i686 -Os -pipe" -DCMAKE_CXX_FLAGS_RELEASE="-flto -fuse-linker-plugin -march=i486 -mtune=i686 -Os -pipe" -DCMAKE_INSTALL_PREFIX=/usr/local -DCMAKE_BUILD_TYPE=Release -DCMAKE_VERBOSE_MAKEFILE=TRUE -Wno-dev -DGOBJECT_INTROSPECTION=true -DSHARED_ONLY=yes -DICAL_GLIB_VAPI=yes ../

[-fno-exceptions fails]

make [0m 35.54s]
sudo make install