[Bug bootstrap/89864] gcc fails to build/bootstrap with XCode 10.2

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89864
Bug 89864 depends on bug 90379, which changed state.

Bug 90379 Summary: Gcc 9.1 fails "make check" on linux due to missing 
MacOS-specific header file
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90379

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED