i am facing issues with newlib, i compiled my code with gcc cross-compiler, and when i use Newlib to printf, my linker will tell me that printf isn’t declared
My compiling and linking script:

i686-elf-gcc -c src/userland/umain/umain.c -o output/file/umain.o -std=gnu99 -ffreestanding -O2 -Wall -Wextra -I "include/include"

i686-elf-gcc -T src/linker.ld -o output/isolate/RCMiracle.bin -ffreestanding -O2 -nostdlib output/file/umain.o output/file/gdt.o output/file/enter.o output/file/function.o output/file/boot.o output/file/kernel.o output/file/jump.o -lgcc -I "include/include"

My code:

#include <stdio.h>
void umain() {
    printf("hello world");
}

Newlib and cross-compiler issues