Generating and then including C source files from another C file can
lead to unexpected compilation errors in certain environments.
Switch the usage text generation from %_usage.c to %_usage.h. The
generated header provides the usage_text definition directly, and
chzdev.c and lszdev.c include the corresponding *_usage.h instead.
Update depfile prerequisites and the clean target to match the new
generated artifacts.
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Jan Polensky <japo@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>