编译lcd文件时出错

printf.c:5: warning: conflicting types for built-in function 'putc'
printf.c: In function 'printf':
printf.c:23: warning: pointer targets in passing argument 1 of 'vsprintf' differ in signedness
printf.c:25: warning: pointer targets in passing argument 1 of 'strlen' differ in signedness
printf.c: In function 'scanf':
printf.c:55: warning: pointer targets in passing argument 1 of 'vsscanf' differ in signedness
ARM-linux-gcc -nostdinc -I/home/jh/arm/lcd/include -Wall -O2 -c -o string.o string.c
string.c:23: warning: conflicting types for built-in function 'putc'
arm-linux-gcc -nostdinc -I/home/jh/arm/lcd/include -Wall -O2 -c -o vsprintf.o vsprintf.c
ar -r -o libc.a div64.o lib1funcs.o ctype.o muldi3.o printf.o string.o vsprintf.o
ar: libc.a: ûÓÐÄǸöÎļþ»òĿ¼
make[1]: *** [libc.a] Error 1
make[1]: Leaving directory `/home/jh/arm/lcd/lib'
arm-linux-ld -Tlcd.lds -o lcd_elf head.o init.o nand.o interrupt.o serial.o lcddrv.o framebuffer.o lcdlib.o main.o lib/libc.a
arm-linux-ld: lib/libc.a: No such file: No such file or directory
make: *** [lcd.bin] Error 1