Compilation fails under XCode 9

I am trying to install root6 using the latest available version from github (master branch). It includes some patches not available in 6.10/06 which allow to compile on XCode 9 (https://github.com/root-project/root/commit/9339de9e644b06d5f77607f83aea118969cab7b6, https://github.com/root-project/root/commit/e16c3fd309e375e8aa781a6495a74a3f89b0cb25, https://github.com/root-project/root/commit/263508429dec26449513914e71f0f71c9ce9485f).

When I try to compile I get several errors like these:

{{/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cmath:313:9: error: no member named 'signbit' in the global namespace
using ::signbit;
~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cmath:314:9: error: no member named 'fpclassify' in the global namespace
using ::fpclassify;
~~^}}

Gist logs available at https://gist.github.com/soleti/fb9f29b969fdc047c9ef7e026ccae276