build: Don't return NULL in functions returning void
This was caught by GCC's (version 13) -Werror=return-type flag, set by openSUSE's default build macros:
error: ‘return’ with a value, in function returning void
This was caught by GCC's (version 13) -Werror=return-type flag, set by openSUSE's default build macros:
error: ‘return’ with a value, in function returning void