[libc][llvm] Forward `LIBC_` options as well in a runtime build

Summary:
We need to forward certain CMake definitions to the runtimes build when
using `-DLLVM_ENABLE_RUNTIMES=libc`. The `libc` project uses both
`LLVM_LIBC` and `LIBC` prefixes. Previously we only forwarded
`LLVM_LIBC`. This patch adds the `LIBC_` prefix, using the underscore to
separate it from `LIBCXX`.

diff --git a/llvm/runtimes/CMakeLists.txt b/llvm/runtimes/CMakeLists.txt
index 5757c1c..dea0075 100644 (file)
--- a/llvm/runtimes/CMakeLists.txt
+++ b/llvm/runtimes/CMakeLists.txt
@@ -180,6 +180,7 @@ foreach(entry ${runtimes})
   endif()
   if(canon_name STREQUAL "LLVMLIBC")
     list(APPEND prefixes "LLVM_LIBC")
+    list(APPEND prefixes "LIBC_")
   endif()
 
   string(FIND ${projName} "lib" LIB_IDX)