struct nodo {
    int data;
    struct nodo* sig;
};

struct nodo* crearNodo(int data){
    struct nodo* nuevo = (struct nodo*)malloc(sizeof(struct nodo));

    nuevo->data = data;
    nuevo->sig = NULL;

    return nuevo;
};

no deberia ser:
nodo* crearNodo(int data){
    struct nodo* nuevo = (struct nodo*)malloc(sizeof(struct nodo));

    nuevo->data = data;
    nuevo->sig = NULL;

    return nuevo;
};

void push(int data, struct nodo** pila){
    struct nodo* nuevo = crearNodo(data);

    nuevo->sig = *pila;
    *pila = nuevo;
}

    struct nodo* pila = crearNodo(10);

    push(2, &pila);

int main(){
    struct nodo* pila = crearNodo(10);

    push(2, &pila);
    push(-12, &pila);

    mostrar(&pila);

    for (size_t i = 0; i < 5; i++)
    {
        printf("Eliminamos %d\n", pop(&pila));
        mostrar(&pila);
    }
    system("pause");
    return 0;
}

function datetoing(string){
    let real_date = {
        'Ene': '01',
        'Feb': '02',
        'Mar': '03',
        'Abr': '04',
        'May': '05',
        'Jun': '06',
        'Jul': '07',
        'Ago': '08',
        'Sep': '09',
        'Oct': '10',
        'Nov': '11',
        'Dic': '12'
    }
    for (key in real_date) {
        string = string.replace(key, real_date[key])
    }
    console.log(string);
    return string;
}

function getDateString(str) {
  let months = ['ENE', 'FEB', 'MAR', 'ABR', 'MAY', 'JUN', 'JUL', 'AGO', 'SEP', 'OCT', 'NOV', 'DIC'];
  if(!str) return;
  if(str.length !== 11) return;
  str = str.toUpperCase();
  if(!months.includes(str.substring(3, 6))) return;
  let dateStr = str.substring(0,3) + (months.indexOf(str.substring(3, 6)) + 1).toString().padStart(2, '0') + str.substring(6);
  return dateStr;
}

let fechas = [
  '12-Ene-2021',
  '04-feb-2020',
  '15-JUN-1976'
]

fechas.forEach(f => {
  console.log( getDateString(f));

function getDateString(str) {
  let months = ['ENE', 'FEB', 'MAR', 'ABR', 'MAY', 'JUN', 'JUL', 'AGO', 'SEP', 'OCT', 'NOV', 'DIC'];
  if(!str) return;
  if(str.length !== 11) return;
  str = str.toUpperCase();
  if(!months.includes(str.substring(3, 6))) return;
  for(let i = 3; i < 6; ++i) {
    if(str.charCodeAt(i) < 65 && str.charCodeAt(i) > 90) return;
  }
  let dateStr = str.substring(0,3) + (months.indexOf(str.substring(3, 6)) + 1).toString().padStart(2, '0') + str.substring(6);
  return dateStr;

function getDateString(str) {
  let months = ['ENE', 'FEB', 'MAR', 'ABR', 'MAY', 'JUN', 'JUL', 'AGO', 'SEP', 'OCT', 'NOV', 'DIC'];
  if(!str) return;
  if(str.length !== 11) return;
  str = str.toUpperCase();
  if(!months.includes(str.substring(3, 6))) return;
  for(let i = 3; i < 6; ++i) {
    if(str.charCodeAt(i) < 65 || str.charCodeAt(i) > 90) return;
  }
  let dateStr = str.substring(0,3) + (months.indexOf(str.substring(3, 6)) + 1).toString().padStart(2, '0') + str.substring(6);
  return dateStr;

note: expected 'char *' but argument is of type 'char'
 void imprimir(char msg[]){