tce-load -i compiletc cmake gobject-introspection-dev vala-dev icu70-dev perl5 libxml2-dev

wget https://github.com/libical/libical/releases/download/v3.0.14/libical-3.0.14.tar.gz

cd libical-3.0.14

mkdir build
cd build

cmake -LAH -DCMAKE_C_FLAGS_RELEASE="-flto -march=i486 -mtune=i686 -Os -pipe" -DCMAKE_CXX_FLAGS_RELEASE="-flto -march=i486 -mtune=i686 -Os -pipe" -DCMAKE_INSTALL_PREFIX=/usr/local -DCMAKE_BUILD_TYPE=Release -DCMAKE_VERBOSE_MAKEFILE=TRUE -DSHARED_ONLY=yes -DICAL_BUILD_DOCS=false -DGOBJECT_INTROSPECTION=true -DICAL_GLIB_VAPI=true -DLIB_INSTALL_DIR=lib -DCMAKE_INSTALL_LIBEXECDIR=lib -DCMAKE_INSTALL_LIBDIR=lib ../

make [0m 40.70s]
sudo make install