- extensions to build:
compiletc.tcz
cmake.tcz
boost-1.65-dev.tcz
squashfs-tools.tcz
zlib_base-dev.tcz
libzstd.tcz

- compiler flags:
   export CFLAGS="-march=i486 -mtune=i686 -Os -pipe"
   export CXXFLAGS="-march=i486 -mtune=i686 -Os -pipe"
   export LDFLAGS="-Wl,-O1"

- build:
   cmake -DCMAKE_INSTALL_PREFIX=/usr/local -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON .
   make
   sudo make DESTDIR=path