Hi, I'm having troubles creating a working Makefile for DPDK app that has source files in subdirectories. Minimal repro I created uses the `helloworld` sample with following changes:
1. Add `tst` subdirectory to project's root 2. Add empty `tst.c` file to such subdirectory 3. Modify original `Makefile`'s SRC-y variable so that it includes `tst/tst.c` When doing that the fist invoke of `make` works just fine and build the app correctly. Subsequent invokes (unless either build directory is cleaned manually or `make clean` is invoked), however, don't track changes in files and always fail on `make[1]: Nothing to be done for 'tst.o'.`. I tried debugging the `Makefile` via `make D=1` but it doesn't output any debug information before failing on abovementioned message. Moving `tst.c` to root folder solved the issue. The issue has been observed with custom Makefiles referencing `app.rte.mk` as well so it's not just helloworld's issue. Petr Houska Azure Intern
