Cannot install on Mohave with Xcode 10.1

[Sean]

$ xcodebuild -version
Xcode 10.1
Build version 10B61

gem install sassc-rails -v '2.1.0'
.
.
.
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cmath:321:9: error: no member named 'isless' in the global namespace
using ::isless;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cmath:322:9: error: no member named 'islessequal' in the global namespace
using ::islessequal;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cmath:323:9: error: no member named 'islessgreater' in the global namespace
using ::islessgreater;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cmath:324:9: error: no member named 'isunordered' in the global namespace
using ::isunordered;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cmath:325:9: error: no member named 'isunordered' in the global namespace
using ::isunordered;
      ~~^
13 errors generated.
make: *** [src/ast.o] Error 1
rake aborted!
Command failed with status (2): [make lib/libsass.so...]

Tasks: TOP => lib/libsass.so
(See full trace by running task with --trace)

rake failed, exit code 1

[Sean]

related

[Sean]

Can be installed with Ruby 2.6.0 ... I was trying with 2.6.1

[Sean]

Seems to have been caused by an Anaconda conflict. After nuking Anaconda it is OK.