Use LLVM_ENABLE_LIBCXX=ON to build the runtimes too

- also add a missing dependency in libompd

Author: luporl

clang/cmake/caches/Release.cmake

@@ -146,6 +146,7 @@ endif()
 if(LLVM_RELEASE_ENABLE_LINK_LOCAL_RUNTIMES)
   set_instrument_and_final_stage_var(LLVM_ENABLE_LIBCXX "ON" BOOL)
   set_instrument_and_final_stage_var(LLVM_STATIC_LINK_CXX_STDLIB "ON" BOOL)
+  set_instrument_and_final_stage_var(RUNTIMES_CMAKE_ARGS "-DLLVM_ENABLE_LIBCXX=ON" STRING)
   set(RELEASE_LINKER_FLAGS "-rtlib=compiler-rt --unwindlib=libunwind")
   if(NOT ${CMAKE_HOST_SYSTEM_NAME} MATCHES "Darwin")
     set(RELEASE_LINKER_FLAGS "${RELEASE_LINKER_FLAGS} -static-libgcc")

openmp/libompd/src/CMakeLists.txt

@@ -11,16 +11,21 @@
 project (libompd)
 cmake_minimum_required(VERSION 3.20.0)
 
+set(LIBOMPD_LD_STD_FLAGS FALSE CACHE BOOL
+  "Use -stdlibc++ instead of -libc++ library for C++ ")
+
+set(LIBCXX_DEP)
+if("libcxx" IN_LIST LLVM_ENABLE_RUNTIMES AND NOT ${LIBOMPD_LD_STD_FLAGS})
+  set(LIBCXX_DEP cxx)
+endif()
+
 add_library (ompd SHARED TargetValue.cpp omp-debug.cpp omp-state.cpp omp-icv.cpp)
 
 # libompd must not link against libomp, there is no code dependency.
-add_dependencies(ompd omp) # ensure generated import library is created first
+add_dependencies(ompd omp ${LIBCXX_DEP}) # ensure generated import library is created first
 
 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
 
-set(LIBOMPD_LD_STD_FLAGS FALSE CACHE BOOL
-  "Use -stdlibc++ instead of -libc++ library for C++ ")
-
 if(${LIBOMPD_LD_STD_FLAGS})
 #  Find and replace/add libstdc++ to compile flags     
    STRING( FIND "${CMAKE_CXX_FLAGS}" "-stdlib=libc++" OUT )