Fix some errors in 8-bit color conversion macros; Fix tools/incdir.sh when g++...

Fix some errors in 8-bit color conversion macros; Fix tools/incdir.sh when g++ is used; Fix bad cast that caused problems with the background window is released

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@4064 42af7a65-404d-4744-a932-0658087f49c3