diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -577,14 +577,8 @@
 
 add_library(cxx-headers INTERFACE)
 add_dependencies(cxx-headers generate-cxx-headers ${LIBCXX_CXX_ABI_HEADER_TARGET})
-# TODO: Use target_include_directories once we figure out why that breaks the runtimes build
-if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC" OR "${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC")
-  target_compile_options(cxx-headers INTERFACE /I${LIBCXX_GENERATED_INCLUDE_DIR}
-                                     INTERFACE /I${LIBCXX_GENERATED_INCLUDE_TARGET_DIR})
-else()
-  target_compile_options(cxx-headers INTERFACE -I${LIBCXX_GENERATED_INCLUDE_DIR}
-                                     INTERFACE -I${LIBCXX_GENERATED_INCLUDE_TARGET_DIR})
-endif()
+target_include_directories(cxx-headers INTERFACE ${LIBCXX_GENERATED_INCLUDE_DIR}
+                                                 ${LIBCXX_GENERATED_INCLUDE_TARGET_DIR})
 
 if (LIBCXX_INSTALL_HEADERS)
   foreach(file ${files})
diff --git a/runtimes/CMakeLists.txt b/runtimes/CMakeLists.txt
--- a/runtimes/CMakeLists.txt
+++ b/runtimes/CMakeLists.txt
@@ -92,6 +92,17 @@
 include(CheckCCompilerFlag)
 include(CheckCXXCompilerFlag)
 
+# CMake omits default compiler include paths, but in runtimes build, we use
+# -nostdinc and -nostdinc++ and control include paths manually so this behavior
+# is undesirable. Resetting CMAKE_{LANG}_IMPLICIT_INCLUDE_DIRECTORIES disables
+# this behavior. See https://gitlab.kitware.com/cmake/cmake/-/issues/19227 for
+# further details no this topic.
+#
+# TODO: We may want to consider filtering out only the paths that are within
+# the toolchain installation and leaving the system paths.
+set(CMAKE_C_IMPLICIT_INCLUDE_DIRECTORIES "")
+set(CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES "")
+set(CMAKE_ASM_IMPLICIT_INCLUDE_DIRECTORIES "")
 
 check_c_compiler_flag("" LLVM_RUNTIMES_LINKING_WORKS)
 if (NOT LLVM_RUNTIMES_LINKING_WORKS)