Put extra compiler flags into a variable so they are not repeated

too many times.
On passing, add some comments and fix indentation a bit.

On passing, i suspect that the following pattern is wrong

	%.eoo: %.o

but in case it will be fixed in a later commit.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@88553 65c4cc65-6c06-0410-ace0-fbb531ad65f3