I'm on a mac and have a vanilla mozilla-central checkout as of: > changeset: 402171:39d5cc0fda5e > fxtree: central > parent: 402170:ae492e161967 > parent: 402126:c3a2ed2ce954 > user: Ryan VanderMeulen <ryanvm@gmail.com> > date: Tue May 30 12:39:46 2017 -0400 > summary: Merge inbound to m-c. a=merge My mozconfig is > ac_add_options --enable-stylo > export LLVM_CONFIG=/Users/tritter/.mozbuild/clang/bin/llvm-config The build fails with > 0:15.37 /Users/tritter/.mozbuild/clang/include/c++/v1/wchar.h:119:15: fatal error: 'wchar.h' file not found, err: true > 0:15.37 /Users/tritter/.mozbuild/clang/include/c++/v1/stdlib.h:94:15: fatal error: 'stdlib.h' file not found, err: true The complete build output is attached (this is the second ./mach build, so there's some things skipped that presumably built fine the first time.)

If you run `xcode-select --install`, does this fix the issue? If so, this is a dupe of bug 1366564.