Fix CXX variables in Makefile

[RCoeurjoly]

Thanks to the comment by @KrystalDelusion in #4244 (comment), the solution was found.

This PR fixes #4244.

[RCoeurjoly]

the emcc pipeline fails, it seems to be related to the CXX variable

[KrystalDelusion]

TIL make automatically provides a default value of CXX = g++, which can be seen as it is g++ returning the error. I suspect make config-clang; make would also run g++ in this case despite the implication of using the clang config; which (in hindsight) is probably why this was setup the way it was. Rather than changing the the CXX assignments, it might make more sense to assign CONFIG=none by default and leave config-gcc/config-clang etc to override as previously intended.

@RCoeurjoly can you check if #4270 also fixes your issue? You'll want to delete Makefile.conf first and then go straight to make (no call to make config-clang)

[RCoeurjoly]

TIL make automatically provides a default value of CXX = g++, which can be seen as it is g++ returning the error. I suspect make config-clang; make would also run g++ in this case despite the implication of using the clang config; which (in hindsight) is probably why this was setup the way it was. Rather than changing the the CXX assignments, it might make more sense to assign CONFIG=none by default and leave config-gcc/config-clang etc to override as previously intended.

@RCoeurjoly can you check if #4270 also fixes your issue? You'll want to delete Makefile.conf first and then go straight to make (no call to make config-clang)

I confirm that PR 4270 fixes this issue.

[KrystalDelusion]

Awesome. I'll close this one in favour of that then.