Compiler warning when building Monitor example

The pragma that is used in qsafeglobal.h is not valid when building C-code. 

Compile warning:
../../../../Src/QtSafeRenderer-2.0.0/include/QtSafeRenderer/../../src/saferenderer/qsafeglobal.h:37:32: warning: option ‘-Wsuggest-override’ is valid for C+/ObjC+ but not for C [-Wpragmas]
37 | #pragma GCC diagnostic ignored "-Wsuggest-override"