cmake: reuse interface lib for compile options if it already exists

Fixes: #43835

In zephyr_library_compile_options() the existence of the compile
options interface library is checked and function returns if it already
exists. This results in #43835 meaning two libraries cannot add the
same option.

This commit fixes this by re-using the already created unique interface
library and link this to the Zephyr library.

Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>
1 file changed