clang -O2  -Wall -Wextra -Werror=implicit-function-declaration unistd/linkat.c -o unistd/linkat -D_GNU_SOURCE -D_BSD_SOURCE -D_ALL_SOURCE -D_DEFAULT_SOURCE  -lm  -lintl
../out/minix/basic/unistd/linkat.o: In function `main':
unistd/linkat.c:(.text+0x3ec): undefined reference to `openat'
unistd/linkat.c:(.text+0x418): undefined reference to `linkat'
unistd/linkat.c:(.text+0x438): undefined reference to `unlinkat'
unistd/linkat.c:(.text+0x450): undefined reference to `unlinkat'
unistd/linkat.c:(.text+0x4c7): undefined reference to `unlinkat'
unistd/linkat.c:(.text+0x4df): undefined reference to `unlinkat'
clang: error: linker command failed with exit code 1 (use -v to see invocation)