OSX: #define __APPLE_USE_RFC_2292

radvd hasn't built on OSX in a long time.  This is the first step
in getting it building again.
add -Wno-cast-align

This cleans up the build on OS X.  I'm not sure how important
these warnings are, so it an investigation is in order to find out
what the deal is.
Removal of unwanted ABRO structure field

Signed-off-by: Bhadram <varkabhadram@gmail.com>
Man page entries of ABRO option

Signed-off-by: Bhadram <varkabhadram@gmail.com>
Modifications to previous patch

Signed-off-by: Bhadram <varkabhadram@gmail.com>
fix spelling error in radvd.conf.5.man
drop singleprocess option

Between 1.8.3 and 1.8.4 (Jan 2, 2012), the option to run radvd as a single
process was deprecated.  Radvd always drops privileges and forks a process
to do privileged operations.

Now that we're about to release version 1.10.0, it's time to remove the
rest of the option.
clean up code style with indent

$ indent -linux -l180 *.c *.h
bump VERSION and CHANGES for 1.10.0-rc2
release 1.10.0