求助！下面这个makefile是什么意思，特别是后面循环的那段，高手请指点

bobodu

# This is the Makefile for the client side device for npu-term.

include Defs.mk
export TOP_DIR
       
TARGET = npu-xscale.o
SRC = clientmain.c clientdma.c clientterm.c clientpci.c

all : .depend $(TARGET)

clean :
        rm -f $(TARGET) *.o *.c~ .depend ../common/header.h
$(TARGET): $(SRC:.c=.o)
        $(LD) -r $^ -o $@

# Special case for clientdma.c because it includes Grunt headers.
clientdma.o : clientdma.c
        $(CC) $(CFLAGS) -c -o $@ $<

../common/header.h : create_header.py
        ./create_header.py
# Clean up the code indenting before doing cvs commit.
# Unfortunately, the local .indent.pro uses --preserve-mtime which preserves
# the mtime for all files. The following hack runs indent on each file and
# touches the files which have changed.
indent:
        @for file in *.[ch] ;do \
                if [ -w "$$file" ]; then \
                        indent $$file ; \
                        x=`cmp $$file $$file~` ; \
                        if [ -n "$$x" ]; then \
                                echo "Indenting $$file" ; \
                                touch $$file ; \
                                fi ; \
                        fi ; \
                done
        @rm -f *~

depend .depend dep : ../common/header.h
        $(CC) $(CFLAGS) -M *.c > $@


ifeq (.depend,$(wildcard .depend))
include .depend
endif
文中加颜色的几行请大家帮我解释一下，谢谢！

codekiller

# This is the Makefile for the client side device for npu-term.

include Defs.mk
export TOP_DIR
        
TARGET = npu-xscale.o
SRC = clientmain.c clientdma.c clientterm.c clientpci.c

all : .depend $(TARGET)

clean :
        rm -f $(TARGET) *.o *.c~ .depend ../common/header.h
＃这是一个make Target，执行make clean时执行这一行指令。
$(TARGET): $(SRC:.c=.o)
        $(LD) -r $^ -o $@

# Special case for clientdma.c because it includes Grunt headers.
clientdma.o : clientdma.c
        $(CC) $(CFLAGS) -c -o $@ $<

../common/header.h : create_header.py
        ./create_header.py
#当header.h不存在或比create_header.py脚本的
#时间更靠前，则执行该脚本。
# Clean up the code indenting before doing cvs commit.
# Unfortunately, the local .indent.pro uses --preserve-mtime which preserves
# the mtime for all files. The following hack runs indent on each file and
# touches the files which have changed.
indent:
        @for file in *.[ch] ;do \
                if [ -w "$$file" ]; then \
                        indent $$file ; \
                        x=`cmp $$file $$file~` ; \
                        if [ -n "$$x" ]; then \
                                echo "Indenting $$file" ; \
                                touch $$file ; \
                                fi ; \
                        fi ; \
                done
        @rm -f *~
# 这个循环明显是对所有.c 和 .h 文件进行 indent 操作。
# indent 我的理解是让c源文件更规范，比如缩进。
# man indent 可以获得详细解释
depend .depend dep : ../common/header.h
        $(CC) $(CFLAGS) -M *.c > $@


ifeq (.depend,$(wildcard .depend))
include .depend
endif
文中加颜色的几行请大家帮我解释一下，谢谢！