LINUX串口编程（貌似-I命令把默认路径屏蔽了）

我在写一个LINUX的串口程序
因为要用到serial.h这个头文件，所以我要在gcc的编译命令里指定一个路径。
编译命令：（用makefile的方式）

[font=Times New Roman]
makefile的内容：
KERNELDIR=/usr/src nux-headers-2.6.24-24-server

CC = arm-none-linux-gnueabi-gcc
CFLAGS = -I$(KERNELDIR)/include nux -Wall
Hostserial:

$(CC) $(CFLAGS) -o Hostserial Hostserial.c
clean:
rm -f Hostserial[/font]


后来，编译出了很多问题，我就先不引用和串口相关的所有函数，我只是在主函数里保留了这一句printf。
printf("Can't open Serial Port!\n");

可是出了一大堆错误。
我个人认为这些错误似乎是，没有找到正确的stdio.h引起的。因为它并没说找不到这个头文件，但是出现了好些很奇怪的错误，比如说，找不到一些别的其实我没引用的头文件
完整错误信息如下：

root@ema3530:/home/ema/COM# make
arm-none-linux-gnueabi-gcc -I/usr/src nux-headers-2.6.24-24-server/include nux -Wall -o Hostserial Hostserial.c
cc1: warning: include location "/usr/include" is unsafe for cross-compilation
cc1: warning: include location "/usr/local/include" is unsafe for cross-compilation
In file included from /usr/include/stdio.h:34,
from Hostserial.c:1:
/usr/src nux-headers-2.6.24-24-server/include nux/stddef.h:4:28: error: linux/compiler.h: No such file or directory
In file included from /usr/include/stdio.h:75,
from Hostserial.c:1:
/usr/include bio.h:332: error: expected specifier-qualifier-list before 'size_t'
/usr/include bio.h:364: error: expected declaration specifiers or '...' before 'size_t'
/usr/include bio.h:373: error: expected declaration specifiers or '...' before 'size_t'
/usr/include bio.h:493: error: expected '=', ',', ';', 'asm' or '__attribute__' before '_IO_sgetn'
In file included from Hostserial.c:1:
/usr/include/stdio.h:312: error: expected declaration specifiers or '...' before 'size_t'
/usr/include/stdio.h:319: error: expected declaration specifiers or '...' before 'size_t'
/usr/include/stdio.h:361: error: expected declaration specifiers or '...' before 'size_t'
/usr/include/stdio.h:363: error: format string argument not a string type
/usr/include/stdio.h:361: warning: conflicting types for built-in function 'snprintf'
/usr/include/stdio.h:365: error: expected declaration specifiers or '...' before 'size_t'
/usr/include/stdio.h:367: error: format string argument not a string type
/usr/include/stdio.h:365: warning: conflicting types for built-in function 'vsnprintf'
/usr/include/stdio.h:678: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'fread'
/usr/include/stdio.h:684: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'fwrite'
/usr/include/stdio.h:706: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'fread_unlocked'
/usr/include/stdio.h:708: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'fwrite_unlocked'
Hostserial.c: In function 'main':
Hostserial.c:10: warning: unused variable 'ch'
Hostserial.c:9: warning: unused variable 'fd'
make: *** [Hostserial] Error 1

我的猜测是：
这种错误，应该是所在的这个路径里，标准头文件不完整
所以，我认为解决的办法应该是保留默认路径，但是，如何指定路径的同时又保留默认路径呢？
这个，我试过修改CPATH，丝毫不起作用

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也或者是别的错误原因，我刚接触LINUX一两个月，很多不懂，希望各位多多指教，谢谢了!