New review comment by Logarithmus on void-packages repository

https://github.com/void-linux/void-packages/pull/31664#discussion_r678624788

Comment:
> I think it would be nice to avoid exporting CXXFLAGS with `CXXFLAGS="..." make test` or even override the variable in the Makefile with `make test CXXFLAGS="..."`

I'm afraid it's not possible https://github.com/void-linux/void-packages/blob/0da27cc76d0765677b4f7dc2c8ce3937489bfe3b/srcpkgs/lsp-plugins/patches/00-makefile-test-remove-cflags.patch