foo.c: In function ‘main’:
foo.c:8:3: warning: implicit declaration of function ‘ptintf’; did you mean ‘printf’? [-Wimplicit-function-declaration]
    8 |   ptintf("****\n");
      |   ^~~~~~
      |   printf
/nix/binutils-2.42/bin/ld: /tmp/ccRPM1Fy.o: in function `main':
foo.c:(.text.startup+0x2a): undefined reference to `ptintf'
collect2: error: ld returned 1 exit status