add check for symlinks

src/read_file.c

@@ -173,7 +173,7 @@ int read_file(char *filename, point_t **points, unsigned int *n) {
 	int j = 0;
     struct stat statbuff;
 
-    stat(filename, &statbuff);
+    lstat(filename, &statbuff);
 	if (access(filename, F_OK) || !S_ISREG(statbuff.st_mode)) {
 		fprintf(stderr, "Error: El archivo \"%s\" no existe!\n", filename);
 		return 1;