B_OS_NAME_LENGTH is 32, char* is 8 (on x64), and this structure
has quite a lot of pointers in it so it is not like we really
needed to save those 24 bytes. Hitting malloc() in here is not
so great, especially because we usually have B_DONT_LOCK_KERNEL_SPACE
turned on, so just inline and avoid it.
Change-Id: I5c94955324cfda08972895826b61748c3b69096a