Ensure that the static structs emitted by the MODULE_DEPEND() and
MODULE_VERSION() macros don't end up as .comm symbols, when all the
version fields are zero.

Normally, such symbols will end up in .bss, but for kernel module
version objects, this can lead to "garbage" version numbers.

Fix this by instructing the compiler to always put these structs in the
.data segment instead.

Reported by: delphij, ae
MFC after: 1 week