diff --git a/llvm/runtimes/CMakeLists.txt b/llvm/runtimes/CMakeLists.txt
--- a/llvm/runtimes/CMakeLists.txt
+++ b/llvm/runtimes/CMakeLists.txt
@@ -178,6 +178,9 @@
   if(canon_name STREQUAL "COMPILER_RT")
     list(APPEND prefixes SANITIZER DARWIN)
   endif()
+  if(canon_name STREQUAL "LLVMLIBC")
+    list(APPEND prefixes "LLVM_LIBC")
+  endif()
 
   string(FIND ${projName} "lib" LIB_IDX)
   if(LIB_IDX EQUAL 0)