[gentoo-dev] How to add -std=c++14 to CXXFLAGS of a cmake.eclass based package?

[Andrey Grozin]

Hello *,

I'm trying to package a new version of sci-visualization/gle which now 
uses cmake. After some patching CMakeLists.txt, it configures 
successfully. But at build time it spits zillion errors

error: ISO C++17 does not allow dynamic exception specifications

The natural thing to try is to add -std=c++14 to CXXFLAGS. So I tried

src_compile() {
    CXXFLAGS="${CXXFLAGS} -std=c++14" cmake_src_compile
}

but this makes no difference, c++17 is still used. How to convince 
cmake_src_compile to use -std=c++14?

Thanks in advance,
Andrey