[Bug bootstrap/89864] [9 regression] gcc fails to build/bootstrap with XCode 10.2

[juergen.reuter at desy dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89864

--- Comment #44 from Jürgen Reuter <juergen.reuter at desy dot de> ---
(In reply to Iain Sandoe from comment #43)
> Created attachment 46110 [details]
> Proof-of-principle path
> 
> Does this work for you?
>  - my local testing says it generates the right wrapped include file.
> 
> (perhaps the constraint on darwin version was too tight in Erik's case)

Sorry for my ignorance, but how do I apply this? Do I just patch, and then
configure and compile/bootstrap as a normal svn checkout, or do I have to do
anything special regarding the fixincludes? And if so, is there a link to some
documentation?