Closed issue by schmidh on void-packages repository

https://github.com/void-linux/void-packages/issues/15714

Description:
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### System

* c++ --version:  
  *c++ (GCC) 9.2.0*
*Copyright (C) 2019 Free Software Foundation, Inc.*
*This is free software; see the source for copying conditions.  There is NO*
*warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.*
* gcc-9.2.0_1:  
  *clang-9.0.0_2*

### Expected behavior
I would love to set the default C++ compiler to clang++ using xbps-alternatives.
### Actual behavior
Trying to set alternative C++ compilers is not possible as there is no alternative group for c++.
/usr/bin/c++ is not a link and actually a regular file being part of the gcc package. There is an alternative group for cc. Many build tools like e.g. CMake use cc and c++ to compile source code.
### Steps to reproduce the behavior