ifdef variable like their use
Restructure genfs_deadlock() and genfs_lock() to always lock before
testing for dead node.  Use ISSET() to test flags, add assertions.

Save the mount for fstrans_done() before genfs_unlock() unlocks the node.
Restructure layer_lock() to always lock before testing for dead node.
Use ISSET() to test flags, add assertions.
Restructure union_lock() to always lock before testing for dead node.
Add two little helpers to lock or unlock a node.  Use "vp" for the
union node and "lockvp" for the node to be locked.  Use ISSET() to
test flags, add assertions.
Add a few dwarf/elf cat pages. Sort list.
#ifdef a variable like its use
add a mask for valid capabilities

also add a comment stating why capabilities start from 0x80
__ppc__ is not supported by GCC, so use __powerpc__.
Add more const to make GCC happy.
Fix a prototype.
When sending, only load mbufs which have a length.  This is especially
useful for fragmented datagrams where the tail of the first packet is
full of nothing.
Rather than having long complicated asm statements, use inlines for
ldrex/strex and let the compiler arrange the code how it wants.
Remove trailing whitespace.
Mark a variable diagnostic-only, from John D. Baker.
XXX This is all wrong and needs new tables and constants - but at least use
constants in the VAX double range for now, so it is compilable with newer
gcc.
Try to avoid using float constants out of range
Avoid double constants out of range
remove some dead code, avoid set but unused variables.
Pass down data_base just in case something actually tries to use it.
Separate common bits for all interfaces implementing virtif hypercalls
from Makefile to Makefile.virtif.  The latter is meant to be .included.