[make] better modularize the build system

-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.

make/macros.mk

@@ -3,3 +3,29 @@ GET_LOCAL_DIR    = $(patsubst %/,%,$(dir $(word $(words $(MAKEFILE_LIST)),$(MAKE
 
 # makes sure the target dir exists
 MKDIR = if [ ! -d $(dir $@) ]; then mkdir -p $(dir $@); fi
+
+# prepends the BUILD_DIR var to each item in the list
+TOBUILDDIR = $(addprefix $(BUILDDIR)/,$(1))
+
+# generate a header file at $1 with an expanded variable in $2
+define MAKECONFIGHEADER
+	@$(MKDIR)
+	@echo generating $1
+	@rm -f $1.tmp; \
+	LDEF=`echo $1 | tr '/\\.-' '_'`; \
+	echo \#ifndef __$${LDEF}_H > $1.tmp; \
+	echo \#define __$${LDEF}_H >> $1.tmp; \
+	for d in `echo $($2) | tr '[:lower:]' '[:upper:]'`; do \
+		echo "#define $$d" | sed "s/=/\ /g;s/-/_/g;s/\//_/g" >> $1.tmp; \
+	done; \
+	echo \#endif >> $1.tmp; \
+	if [ -f "$1" ]; then \
+		if cmp "$1.tmp" "$1"; then \
+			rm -f $1.tmp; \
+		else \
+			mv $1.tmp $1; \
+		fi \
+	else \
+		mv $1.tmp $1; \
+	fi
+endef