MSVC generates the following for those tests:
warning C4996: '_open': This function or variable may be unsafe. Consider using _sopen_s
instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online
help for details.
We need to set the define before any C runtime headers are included, so
do it right away, it doesn't do any harm on other compilers.
Change-Id: Ia25afb87934058c3f27e63820eeb2db063a627f1
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
5a2ee82f2c