Fix bug that prevented XCode to switch between Release and Debug build type.
Fix bug that prevented XCode to switch between Release and Debug build type.

simonkrogmann/libzeug,j-o/libzeug,j-o/libzeug,mjendruk/libzeug,p-otto/libzeug,j-o/libzeug,cginternals/libzeug,lanice/libzeug,hpi-r2d2/libzeug,hpi-r2d2/libzeug,j-o/libzeug,p-otto/libzeug,cginternals/libzeug,cginternals/libzeug,kateyy/libzeug,p-otto/libzeug,kateyy/libzeug,simonkrogmann/libzeug,mjendruk/libzeug,lanice/libzeug,cginternals/libzeug,mjendruk/libzeug,lanice/libzeug,lanice/libzeug,kateyy/libzeug