GTK4 with textbox

main.c

// gcc main.c `pkg-config --cflags --libs gtk4`                                                                                                                                                                                            Too many errors emitted, stopping now
  
#include <gtk/gtk.h>                                                                                                                                                                                                                       'gtk/gtk.h' file not found
  
static void activate(GApplication* app, gpointer user_data) {                                                                                                                                                                              Unknown type name 'gpointer'
  GtkWidget* window = gtk_window_new();                                                                                                                                                                                                    Call to undeclared function 'gtk_window_new'; ISO C99 and later do not support implicit function declarations
  gtk_window_set_application(GTK_WINDOW(window), GTK_APPLICATION(app));                                                                                                                                                                    Use of undeclared identifier 'window'
  
  GtkWidget* entry = gtk_entry_new();                                                                                                                                                                                                      Call to undeclared function 'gtk_entry_new'; ISO C99 and later do not support implicit function declarations
  gtk_entry_set_input_hints(GTK_ENTRY(entry), GTK_INPUT_HINT_PRIVATE);                                                                                                                                                                     Use of undeclared identifier 'GTK_INPUT_HINT_PRIVATE'
  gtk_window_set_child(GTK_WINDOW(window), entry);                                                                                                                                                                                         Use of undeclared identifier 'entry'
  
  gtk_window_present(GTK_WINDOW(window));
}
  
int main (int argc, char* argv[])  {
  GtkApplication* app = gtk_application_new(NULL, G_APPLICATION_DEFAULT_FLAGS);
  g_signal_connect(G_OBJECT(app), "activate", G_CALLBACK(activate), NULL);
  return g_application_run(G_APPLICATION(app), argc, argv);
}