mesa: 46110c5d56eb7a2d3c69b2d8565c7631541511b1 (master 10.6.0-devel)
MinGW build error
main/light.c: In function '_mesa_light':
main/light.c:159:62: error: 'M_PI' undeclared (first use in this function)
light->_CosCutoff = (GLfloat) (cos(light->SpotCutoff * M_PI / 180.0));
Hmm, I don't see that here. The patch is simple though. Will post for review.
Fixed with commit 06ed81044fc6b1dee90e67de314f81150746e104