‘isdigit’ was not declared in this scope" in `dng_string.cpp`
While building digiKam, I encountered an error in the file core/libs/dngwriter/extra/dng_sdk/dng_string.cpp.
The error pointed to the use of isdigit without declaration. To address this issue, I added #include <cctype>
at the beginning of the file, ensuring the proper declaration of the isdigit function. This modification successfully resolved the compilation error.