#396 QP 8.1.1, file qsafe.h compilation errors

[Quantum Leaps]

The file qsafe.h contains C++-specific code, which causes compilation errors when QP/C source code is compiled as C++.

NOTE: Compiling C code as C++ offers certain benefits (e.g., stronger type checking and better compiler diagnostics). Therefore, some developers might prefer to compile QP/C as C++, and they should be able to do so.