Compile warnings when using Platform.io

[newone996]

When compiling in Platform.io I am getting the following warning:

.pio/libdeps/megaatmega2560/Easy Nextion Library/src/EasyNextionLibrary.cpp: In member function 'String EasyNex::readStr(String)': .pio/libdeps/megaatmega2560/Easy Nextion Library/src/EasyNextionLibrary.cpp:144:45: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(_tempChar == 0xFF || _tempChar == 0xFFFFFFFF){ // If the read byte is the end command byte, ~~~~~~~~~~^~~~~~~~~~~~~ .pio/libdeps/megaatmega2560/Easy Nextion Library/src/EasyNextionLibrary.cpp: In member function 'uint32_t EasyNex::readNumber(String)': .pio/libdeps/megaatmega2560/Easy Nextion Library/src/EasyNextionLibrary.cpp:245:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(_tempChar == 0xFF || _tempChar == 0xFFFFFFFF){ // If the read byte is the end command byte,