taskd: add patch to fix musl build issue

taskd: add patch to fix musl build issue

taskd checks for `get_current_dir_name` but forgets to add a `cmakedefine`
in cmake.h.in, so `HAVE_GET_CURRENT_DIR_NAME` is always undefined.

CMake detects correctly that the musl C library defines `get_current_dir_name`.
However, as `HAVE_GET_CURRENT_DIR_NAME` is not set, the block of code evaluated
cannot be compiled as musl does not define `PATH_MAX`.

Reported upstream:
https://bug.tasktools.org/browse/TD-120

Fixes:
http://autobuild.buildroot.net/results/121/121aa15235e06c80d65428626da5a2da9d11c9ba/

Signed-off-by: Jörg Krause <joerg.krause@embedded.rocks>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>