https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89879
Bug ID: 89879 Summary: GCC fails to build on macOS 10.14.4 Product: gcc Version: 8.3.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: bootstrap Assignee: unassigned at gcc dot gnu.org Reporter: schnetter at gmail dot com Target Milestone: --- Created attachment 46053 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46053&action=edit patch After upgrading to macOS 10.14.4, GCC 8.3.0 does not build any more. The issue is unrelated to Spack; even a vanilla GCC fails to install. This StackExchange issue <https://apple.stackexchange.com/questions/355049/compilation-error-with-mojave-error-atomic-does-not-name-a-type/355103#355103> is a description of the problem including the actual error message. The underlying problem is that a macOS header file uses the _Atomic keyword for C++ code, although this is only a C keyword. I assume that Clang defines _Atomic even for C++ code as extension to the C++ standard. The proper solution is probably adding a fixinclude for GCC.