Looks like the wiringPi library was either not built/installed successfully, or the toolchain synchronization after it was built did not complete.
Could you confirm that the “build” command for wiringPi succeeded and that the libwiringPi.so file is present in /usr/lib on your Raspberry Pi and in the corresponding directory inside the toolchain’s sysroot.
Thanks for checking this. Please also check that the .so file is present in the cross-toolchain’s sysroot directory.
If it does, please try adding “-Wl,-verbose” to the linker flags and check the linker output. It will show where exactly the linker is searching for the library.
If nothing helps, please attach a screenshot of the error and the build output with the verbose linker mode turned on.