Eclipse CDT: no rule to make target all

You need to change your project settings so that Eclipse-CDT manages your Makefiles for you.

1. Select Project->Properties from the menu bar.
2. Click C/C++ Build on the left in the dialog that comes up.
3. Under the Builder Settings tab on the right, select “Generate Makefiles automatically” under the Makefile generation section.
4. Hit OK and build again.