-> install build dependencies:
$ tce-load -wi compiletc 

-> per TC wiki, for maximum compatibility:
$ export CFLAGS="-mtune=generic -Os -pipe"
$ export CXXFLAGS="-mtune=generic -Os -pipe"
$ export LDFLAGS="-Wl,-O1"

-> finally:
$ ./configure --prefix=/usr/local
$ make
$ mkdir /opt/dest; sudo make DESTDIR=/opt/dest install

-> some TCL-specific tweaks:
- so that applications can access their files in /tmp/tcloop/foo: $ cd /usr/local/etc/firejail; sed -i 's/private-tmp//' *
- similarly (and so that firefox.profile works), comment-out this line in /usr/local/etc/firejail/disable-exec.inc: noexec /tmp
- so chromium-browser.profile works, comment-out this line in /usr/local/etc/firejail/disable-common.inc: blacklist ${PATH}/nc
- make sure that when the .tcz is created, the binaries retain their attributes (owned by root:root, 755 permissions, SUID bit on firejail)