Split the MAKECONFIGHEADER macro into the part that generates
the header and the part that tests if you should replace the
target file with the generated one.
-Each module's rules.mk defines a seperate linkage unit. Each
module can have a private set of CFLAGS, DEFINES, INCLUDES, and so
forth.
-Files to be compiled are now added by source, not object.
Most rules.mk files can be converted easily by following these steps:
1) add 'MODULE := $(LOCAL_DIR)' near the top of the file
2) change OBJS += to MODULE_SRCS += and list source files instead of .os
3) add 'include make/module.mk' at the bottom of the file
See make/module.mk for directions.
