[llvm] [CMake] Make precompiled headers opt-in for ccache builds (PR #141927)

[Aiden Grossman via llvm-commits]

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@@ -289,6 +289,12 @@ if(LLVM_CCACHE_BUILD)
     set(LLVM_CCACHE_PARAMS "CCACHE_CPP2=yes CCACHE_HASHDIR=yes CCACHE_SLOPPINESS=pch_defines,time_macros"
         CACHE STRING "Parameters to pass through to ccache")
 
+    # Using precompiled headers with ccache builds can result in intermittent CI failures
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boomanaiden154 wrote:

Can you be more specific about what the error is here?

https://github.com/llvm/llvm-project/pull/141927