directories are not executables

This can be reproduced using `./.`. It errors when trying to execute
while it should not even return it as an executable in the first place.

src/path.c

@@ -13,23 +13,25 @@
 #include <unistd.h>
 #include <libft.h>
 #include <ft_printf.h>
+#include <sys/stat.h>
 #include "env.h"
 #include "path.h"
 
 static struct s_program	get_executable(char *pathname)
 {
-	struct s_program program;
+	struct stat			statbuf;
+	struct s_program	program;
 
 	ft_memset(&program, '\0', sizeof(struct s_program));
-	if (access(pathname, X_OK) == 0)
+	if (stat(pathname, &statbuf) == -1)
+		program.type = NOTFOUND;
+	else if (S_ISREG(statbuf.st_mode) && access(pathname, X_OK) == 0)
 	{
 		program.type = EXECUTABLE;
 		ft_strncpy(program.pathname, pathname, PATH_MAX);
 	}
 	else
-	{
 		program.type = NOTFOUND;
-	}
 	return (program);
 }