[cannot compile in 4gb ram]

tce-load -i compiletc zip unzip gperf perl_archive_zip automake libtool-dev gtk3-dev gtk2-dev cups-dev curl-dev gst-plugins-base-dev lcms2-dev librsvg-dev libxslt-dev nss-dev libsane-dev bash tar coreutils dbus-glib-dev wget neon-dev python3.6-dev libbluetooth-dev dconf-dev desktop-file-utils nasm zenity glu-dev libatomic_ops-dev hunspell-dev libxml2-bin redland-dev boost-1.65-dev glm-dev libexttextcat-dev clucene-dev harfbuzz-icu-dev icu61-bin poppler07-dev serf-dev apr-dev krb5-dev

http://download.documentfoundation.org/libreoffice/src/6.4.0/libreoffice-6.4.0.3.tar.xz
https://github.com/LibreOffice/core/ [for fixes]

cd /usr/local/bin
sudo rm python
sudo ln -s python3.6 python

cd libreoffice-6.4.0.3

sed -e "/gzip -f/d" -e "s|.1.gz|.1|g" -i bin/distro-install-desktop-integration
sed -e "/distro-install-file-lists/d" -i Makefile.in

sed -e '/JAVA_SOURCE_VER/s/6/7/' -e '/JAVA_TARGET_VER/s/6/7/' -i configure.ac

sed -e 's/globalParams = new GlobalParams()/globalParams.reset(new GlobalParams())/' -i sdext/source/pdfimport/xpdfwrapper/wrapper_gpl.cxx

sed -e 's/printPath( GfxPath/printPath(const GfxPath/' -e 's/  GfxSubpath/ const GfxSubpath/' -i sdext/source/pdfimport/xpdfwrapper/pdfioutdev_gpl.*

edit configure
    if test "$gccvisbroken" = "no"; then
        as_fn_error $? "Your gcc is not -fvisibility=hidden safe. This is no longer supported." "$LINENO" 5

PGCONFIG=/usr/local/pgsql11/bin/pg_config CC="gcc -flto -fuse-linker-plugin -mtune=generic -Os -pipe" CXX="g++ -flto -fuse-linker-plugin -mtune=generic -Os -pipe" ./autogen.sh --prefix=/usr/local --localstatedir=/var --without-help  --without-myspell-dicts --without-fonts --without-java --without-junit --without-system-dicts --disable-odk --disable-firebird-sdbc --enable-release-build=yes  --enable-python=system --with-parallelism=4 --disable-extensions --without-doxygen --with-system-apr --with-system-bluez --with-system-boost --with-system-cairo --with-system-clucene --with-system-curl -with-system-epoxy --with-system-expat --with-system-glm --with-system-graphite --with-system-harfbuzz --with-system-hunspell --with-system-icu --with-system-jpeg --with-system-lcms2 --with-system-libatomic_ops --with-system-libexttextcat --with-system-libpng --with-system-libxml --with-system-neon --with-system-nss -with-system-odbc --with-system-openldap --with-system-openssl --with-system-poppler --with-system-postgresql --with-system-redland --with-system-sane --with-system-serf --with-system-zlib

checking for /run/user/1001... no

--with-lang='fr en-GB' [default en-US]

time make build-nocheck [3h 56m 19s]
sudo make distro-pack-install