[compiler-rt] [compiler-rt] Use installed libc++(abi) for tests instead of build tree (PR #115077)

[Alexander Richardson via llvm-commits]

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@@ -680,15 +680,16 @@ macro(add_custom_libcxx name prefix)
 
   ExternalProject_Add(${name}
     DEPENDS ${name}-clobber ${LIBCXX_DEPS}
-    PREFIX ${CMAKE_CURRENT_BINARY_DIR}/${name}
+    PREFIX ${prefix}
     SOURCE_DIR ${LLVM_MAIN_SRC_DIR}/../runtimes
-    BINARY_DIR ${prefix}
+    BINARY_DIR ${prefix}/build
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arichardson wrote:

No, the install directory is ${prefix}, so it uses the installed headers now instead of the build tree.

https://github.com/llvm/llvm-project/pull/115077