The .input
attribute expects the name of a variable, not a list of files. Try taking away the $$
and just use xxd.input = SHADERS
.
.depends
, on the other hand, expects a list of files, so use xxd.depends = $$SHADERS
.
If you set .variable_out
to HEADERS
, SOURCES
, or OBJECTS
, the compiler will run. However, if you set .variable_out
to another variable name, you must also set .CONFIG = target_predeps
in order for the compiler to run.