openjdk6 makefile changes

[Kelly O'Hair]

Joe,

Let me know if you want these changes in b20 or later in b21:

6931763: sanity checks broken with latest cygwin, newer egrep -i  
option problems
6728161: Add SKIP_BOOT_CYCLE feature to create boot jdk and use it  
during build
6960853: Cleanup makefiles, remove unused vars etc.

http://javaweb.sfbay.sun.com/~ohair/webrevs/openjdk6/make-changes/webrev/

Tried to bring in everything from jdk7 that was missing from ./ 
Makefile, ./test/Makefile,
./jdk/test/Makefile, etc.
Also lots of cleanup and deleting of stuff not needed in the openjdk6  
forest.

gmake SKIP_BOOT_CYCLE=false seems to work now.

-kto