Two changes to shut up GCC:
* __GLIBC__ was checked unconditionally;
this made for a very messy build on musl.
* int fd in chvt is always initialized; GCC 3.4 does not recognize this.
init: don't use VT_OPENQRY.

The original codepath checks if there is a VT available,
and if there isn't sets TERM to vt102 (unless TERM is set to something
other than "linux").
Otherwise, TERM is set to "linux" if it is not already set.

However, we can rely on getty/... to set TERM if "linux" is not suitable.
This has the benefit of dropping a slightly messy section.