add comments for depends

+# generate the module info to Makefile
+#
 # params:
-# $SRS_OBJS the objs directory. ie. objs
-# $SRS_MAKEFILE the makefile name. ie. Makefile
-# $MODULE_DIR the module dir. ie. src/os/linux
-# $MODULE_ID the id of module. ie. CORE
-# $MODULE_DEPENDS array, the denpend MODULEs id. ie. (CORE OS)
-# $ModuleLibIncs array, the depend 3rdpart library includes. ie. (objs/st-1.9/obj objs/libx264/obj)
-# $MODULE_FILES array, the head/cpp files of modules. ie. (public log)
-# 
+#     $SRS_OBJS the objs directory. ie. objs
+#     $SRS_MAKEFILE the makefile name. ie. Makefile
+#
+#     $MODULE_DIR the module dir. ie. src/os/linux
+#     $MODULE_ID the id of module. ie. CORE
+#     $MODULE_DEPENDS array, the denpend MODULEs id. ie. (CORE OS)
+#     $ModuleLibIncs array, the depend 3rdpart library includes. ie. (objs/st-1.9/obj objs/libx264/obj)
+#     $MODULE_FILES array, the head/cpp files of modules. ie. (public log)
+#     
 # returns:
-# $MODULE_OBJS array, the objects of the modules.
+#     $MODULE_OBJS array, the objects of the modules, used for link the binary
 
 FILE=${SRS_OBJS}/${SRS_MAKEFILE}
+echo "#####################################################################################" >> ${FILE}
+echo "# the ${MODULE_ID} module." >> ${FILE}
+echo "#####################################################################################" >> ${FILE}
+echo  >> ${FILE}
 
 # INCS
-INCS_NAME="${MODULE_ID}_INCS"
-echo "# the ${MODULE_ID} module." >> ${FILE}
+echo "# INCS for ${MODULE_ID}, headers of module and its depends to compile" >> ${FILE}
+#
+# the public include files, for example:
+#       CORE_MODULE_INCS = -Isrc/core
 echo "${MODULE_ID}_MODULE_INCS = -I${MODULE_DIR} " >> ${FILE}
+#
+# the private include files, for example:
+#       CORE_INCS = -Isrc/core -Iobjs/st -Iobjs -Iobjs/hp -Iobjs 
+#       MAIN_INCS = -Isrc/main $(CORE_MODULE_INCS) -Iobjs/st -Iobjs
+# where the public will be used for other modules which depends on it.
+INCS_NAME="${MODULE_ID}_INCS"
+#
+# current module header files
 echo -n "${INCS_NAME} = -I${MODULE_DIR} " >> ${FILE}
+#
+# depends module header files
 for item in ${MODULE_DEPENDS[*]}; do
     DEP_INCS_NAME="${item}_INCS"do
     DEP_INCS_NAME="${item}_MODULE_INCS"
     echo -n "\$(${DEP_INCS_NAME}) " >> ${FILE}
 done
+#
+# depends library header files
 for item in ${ModuleLibIncs[*]}; do
     echo -n "-I${item} " >> ${FILE}
 done
-echo "" >> ${FILE}
+echo "" >> ${FILE}; echo "" >> ${FILE}
 
 # DEPS
+echo "# DEPS for ${MODULE_ID}, the depends of make schema" >> ${FILE}
+# depends on headers of self module, for example:
+#       CORE_DEPS =  src/core/srs_core.hpp
 DEPS_NAME="${MODULE_ID}_DEPS"
 echo -n "${DEPS_NAME} = " >> ${FILE}
 for item in ${MODULE_FILES[*]}; do
@@ -36,6 +60,8 @@ for item in ${MODULE_FILES[*]}; do
         echo -n " ${HEADER_FILE}" >> ${FILE}
     fi
 done
+# depends on other modules, for example:
+#       MAIN_DEPS =  $(CORE_DEPS)
 for item in ${MODULE_DEPENDS[*]}; do
     DEP_DEPS_NAME="${item}_DEPS"
     echo -n " \$(${DEP_DEPS_NAME}) " >> ${FILE}
@@ -43,6 +69,7 @@ done
 echo "" >> ${FILE}; echo "" >> ${FILE}
 
 # OBJ
+echo "# OBJ for ${MODULE_ID}, each object file" >> ${FILE}
 MODULE_OBJS=()
 for item in ${MODULE_FILES[*]}; do
     CPP_FILE="${MODULE_DIR}/${item}.cpp"
@@ -56,7 +83,7 @@ for item in ${MODULE_FILES[*]}; do
 done
 echo "" >> ${FILE}
 
-# Makefile
+# parent Makefile, to create module output dir before compile it.
 echo "	mkdir -p ${SRS_OBJS}/${MODULE_DIR}" >> ${SRS_MAKEFILE}
 
 echo -n "generate module ${MODULE_ID} ok"; echo '!';