cmake: change construct_add_custom_command_for_linker_pass into macro

Change construct_add_custom_command_for_linker_pass from function into
macro. The purpose of the function was to set the output variable to a
string that would be fed to add_custom_command. This meant all use
required a two-step procedure and an intermediate
variable (custom_command).

The environmental leakage from a macro in this case is small, so let's
just simplify to a macro and avoid the two-step.

No functional change expected.

Signed-off-by: Mark Ruvald Pedersen <mped@oticon.com>
1 file changed