gl_PointCoord not available with desktop OpenGL

Since Qt 5.7 my shader fails to compile with the following error message:

QOpenGLShader::compile(Fragment): ERROR: 0:? : 'gl_PointCoord' : variable is not available in current GLSL version

The shader version is set to 110. I'm using OpenGL 4.3 on Windows 7. It worked fine with up to Qt 5.6. In Qt 5.7 and 5.8 it works only when using ANGLE.