[MSVC] gzlib failed due to error C2065: 'O_RDONLY': undeclared identifier

The MSVC's recently changes broken zlib when building QT6, the CRT does not define those macros because they are not standard C, can you help look? Our workaround: add "/D_CRT_DECLARE_NONSTDC_NAMES" to define them. The next version of VS will have this behavior.

Repro steps:

1. open VS 2019 x64 Tools command
2. git clone git://code.qt.io/qt/qt5 F:\gitP\qt\qt6
3. cd F:\gitP\qt\qt6
4. git checkout 6.2
5. perl init-repository
6. mkdir F:\gitP\qt\qt6\build_amd64
7. cd F:\gitP\qt\qt6\build_amd64
8. ..\configure -developer-build -release -confirm-license -opensource -nomake tests
9. cmake --build . --parallel --verbose

Error info:
F:\gitP\qt\qt6\qtbase\src\3rdparty\zlib\src\gzlib.c
F:\gitP\qt\qt6\qtbase\src\3rdparty\zlib\src\gzlib.c(231): error C2065: 'O_RDONLY': undeclared identifier
F:\gitP\qt\qt6\qtbase\src\3rdparty\zlib\src\gzlib.c(232): error C2065: 'O_WRONLY': undeclared identifier
F:\gitP\qt\qt6\qtbase\src\3rdparty\zlib\src\gzlib.c(232): error C2065: 'O_CREAT': undeclared identifier
F:\gitP\qt\qt6\qtbase\src\3rdparty\zlib\src\gzlib.c(237): error C2065: 'O_TRUNC': undeclared identifier
F:\gitP\qt\qt6\qtbase\src\3rdparty\zlib\src\gzlib.c(238): error C2065: 'O_APPEND': undeclared identifier