Did you want gluPerspective or gluLookAt? These aren't part of GLUT, just GLU, which will always be there if OpenGL is there, so they're perfectly fine to use in your app.
However, if you want to use glFrustum, try
float halfWidth = tan(0.5 * fovHorizontal);
float halfHeight = tan(0.5 * fovVertical);
glFrustum(-halfWidth, halfWidth, -halfHeight, halfHeight, zNear, zFar);
That's what gluPerspective does internally (except it calculates fovHorizontal as aspect * fovVertical), so that should do it.