[clang] [CMake][Release] Stop linking against stage1 runtimes (PR #164017)

[Cullen Rhodes via cfe-commits]

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@@ -44,6 +44,19 @@ set(LLVM_RELEASE_ENABLE_LTO THIN CACHE STRING "")
 set(LLVM_RELEASE_ENABLE_PGO ON CACHE BOOL "")
 set(LLVM_RELEASE_ENABLE_RUNTIMES ${DEFAULT_RUNTIMES} CACHE STRING "")
 set(LLVM_RELEASE_ENABLE_PROJECTS ${DEFAULT_PROJECTS} CACHE STRING "")
+
+# This option enables linking stage2 clang statically with the runtimes
+# (libc++ and compiler-rt) from stage1.  In theory this will give the
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c-rhodes wrote:

sorry you can ignore me, I was looking at `STAGE1_RUNTIMES` being set regardless of this flag but of course that's only to build, the linking bit comes later.

https://github.com/llvm/llvm-project/pull/164017