nitg-s: do not color undead types

`undead` things are dead things but that are referenced in C code, thus
need a definition to permit the link.

undead types are no more colored but the C declarations need to remain.

Signed-off-by: Jean Privat <jean@pryen.org>
nitg-s: remove partial_types

rta and nitg-s now do the right thing for detecting and compiling type tests.
The partial types hack is thus useless.

Signed-off-by: Jean Privat <jean@pryen.org>