make STANDALONE=n
or
make STANDALONE=y
According to the readme STANDALONE=y is the default, and when in that mode the linker includes are ignored (for example -Wl,-L=... gcc options) and replaced by some fixed versions of the .a libraries. Linkage still worked in my case but the code didn't work properly afterwards. Espressif must have made some backwards incompatible changes to their implementation. The esp-open-rtos can't be compiled in standalone mode either.