리눅스에서 OpenGL사용하려 하는데, 에러 좀 봐주세요.

// Bounce.c
// Demonstrates a simple animated rectangle program with GLUT
// OpenGL SuperBible, 2nd Edition
// Richard S. Wright Jr.

// #include <windows.h>
#include <gl/glut.h>

// Initial square position and size
GLfloat x1 = 100.0f;
GLfloat y1 = 150.0f;
GLsizei rsize = 50;

// Step size in x and y directions
// (number of pixels to move each time)
GLfloat xstep = 1.0f;
GLfloat ystep = 1.0f;

// Keep track of windows changing width and height
GLfloat windowWidth;
GLfloat windowHeight;

// Called to draw scene
void RenderScene(void)
{
// Clear the window with current clearing color
glClear(GL_COLOR_BUFFER_BIT);

// Set current drawing color to red
// R G B
glColor3f(1.0f, 0.0f, 0.0f);

// Draw a filled rectangle with current color
glRectf(x1, y1, x1+rsize, y1+rsize);

// Flush drawing commands
glutSwapBuffers();
}

// Called by GLUT library when idle (window not being
// resized or moved)
void TimerFunction(int value)
{
// Reverse direction when you reach left or right edge
if(x1 > windowWidth-rsize || x1 < 0)
xstep = -xstep;

// Reverse direction when you reach top or bottom edge
if(y1 > windowHeight-rsize || y1 < 0)
ystep = -ystep;

// Check bounds. This is incase the window is made
// smaller and the rectangle is outside the new
// clipping volume
if(x1 > windowWidth-rsize)
x1 = windowWidth-rsize-1;

if(y1 > windowHeight-rsize)
y1 = windowHeight-rsize-1;

// Actually move the square
x1 += xstep;
y1 += ystep;

// Redraw the scene with new coordinates
glutPostRedisplay();
glutTimerFunc(33,TimerFunction, 1);
}

// Setup the rendering state
void SetupRC(void)
{
// Set clear color to blue
glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
}

// Called by GLUT library when the window has chanaged size
void ChangeSize(GLsizei w, GLsizei h)
{
// Prevent a divide by zero
if(h == 0)
h = 1;

// Set Viewport to window dimensions
glViewport(0, 0, w, h);

// Reset coordinate system
glMatrixMode(GL_PROJECTION);
glLoadIdentity();

// Keep the square square, this time, save calculated
// width and height for later use
if (w <= h)
{
windowHeight = 250.0f*h/w;
windowWidth = 250.0f;
}
else
{
windowWidth = 250.0f*w/h;
windowHeight = 250.0f;
}

// Set the clipping volume
glOrtho(0.0f, windowWidth, 0.0f, windowHeight, 1.0f, -1.0f);

glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}

// Main program entry point
void main(void)
{
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
glutCreateWindow("Bounce");
glutDisplayFunc(RenderScene);
glutReshapeFunc(ChangeSize);
glutTimerFunc(33, TimerFunction, 1);

SetupRC();

glutMainLoop();
}