Make all the ELF relocation constants available.

BSD thinks you should only get the relocation constants for your target
architecture, but it's often useful to have them all available at once.
Rearrange the headers to enable that.

Also update the (modified) NetBSD files to CVS HEAD.

Also remove the unused BSDism R_TYPE.

Bug: N/A
Test: builds
Change-Id: Iad5ef29192a732696e2b36af35144a9ca116aa46