Fix static linking with libde265 on Windows
Please read #1506
I don't think this is a good solution. LIBDE265_STATIC_BUILD is an implementation detail within libde265 and it should not be exposed or used by any client software (including libheif). Furthermore, this patch assumes that libde265 is built statically exactly when libheif is built statically even though these choices are not related in general.
However, I also do not have a better solution. Support for static linking is not in the main scope of the libraries since it usually indicates a license violation.
I respect your opinion.
If there are no further discussions, please close the pull request without merging it.
Transitive usage requirements shouldn't be hardcoded.
I understand. Thank you very much.