I'm using Keil DS-5 for about 3 months, works well, but today, he stopped to generate the executable! The date of the stripped hello stopped at 08:15 today, the more I change the fonts, the executable does not change!
That looks like nothing has changed/needs rebuilding (as far as the Makefile knows). Maybe you want to try "Clean Project"? Or maybe there are dependencies missing from the Makefile?