[tlbuild] Victory on El Capitan - Thanks Mojca

[Richard Koch]

Folks,

I've had problems with XeTeX in TeX Live 2018  on the Mac. Although I knew intellectually that Apple extended the Objective C compiler to simultaneously compile C++ code, that fact didn't propagate to my gut and bones. 

Mojca Miklavec suggested

	export OBJCXX="clang++ --std=c++11"
	./Build 

That works! Others have been telling me the same idea, but it is the OBJCXX that did the trick. Many thanks!


Karl, this is essentially equivalent to the patch which Akira Kakuto and Hironobu proposed. The advantage of their patch is that if anyone else wants to compile TeX Live on the Mac after the release, they won't have to go through the debugging done here.
But I'm no longer desperate to have the patch.

Dick Koch