Make C++ standard to be enable from cmake settings:
User will be able choosing C++ language standard by selecting cmake variable BUILD_CPP_STANDARD.
For correct working, CMAKE_CXX_STANDARD cmake built-in variable should be available.
To enable CMAKE_CXX_STANDARD, minimum CMAKE version has been updated to 3.1.
Available next standard items:
C++11
C++14
C++17
C++20
C++23
This issue consists from several steps to achive main goal:
1) Configuratiuon, CMake - allow selecting C++ standard.
2) Require minimum CMAKE version 3.1 (for enabling CMAKE_CXX_STANDARD).
3) More flexible CMAKE_CXX_COMPILER_ID identification (fixups previous commit!)
4) Add description of new CMAKE variable `BUILD_CPP_STANDARD` into documentation.
5) Update CMAKE requirements in documentation.
6) Set C++11 standard for several projects.
Use of Cotire tool is introduced for acceleration of CMake builds, by usage of precompiled headers.
CMake option BUILD_USE_PCH is added to enable / disable use of precompiled headers
When precompiled headers are used, additional compiler macros are defined globally in the build system to avoid problems due to different order of included files:
- NOMINMAX is defined on Windows to prevent defining "min" and "max" as macros by windows.h
- STRSAFE_NO_DEPRECATE and _SCL_SECURE_NO_WARNINGS are defined on Windows to prevent declaring functions of standard C library as deprecated by #pragma, and other warnings in system headers
- GL_GLEXT_LEGACY and GLX_GLEXT_LEGACY are defined to ensure that only OCCT's own glext.h is used
- __STDC_FORMAT_MACROS is defined to have standard C print format macros always defined
Code is corrected to avoid conflicts with system headers and in case of compiling together as unity builds (partially):
- Some locally defined variables in TKV3d, TKHLR are renamed to be unique
- Duplicated definitions of macros and global functions are eliminated in TKSTEP
- Useless header WNT_UInt.hxx is removed
- Usage of local variables conflicting with X11 macro is avoided in Draw_Viewer.cxx
- Local variables in AIS_ConcentricRelation.cxx are renamed to avoid conflict with macros defined in windows.h
- HXX files containing code are renamed to PXX or merged with corresponding CXX files.
IVtkTools classes are corrected to avoid compiler warnings disabled in non-PCH builds by inclusion of VTK headers.
Useless pragmas disabling warnings on MSVC are removed
