diff --git a/Makefile b/Makefile
index eeac2dbff..e96c53eef 100644
--- a/Makefile
+++ b/Makefile
@@ -185,6 +185,7 @@ build/compiler-rt.BUILT: build/llvm.BUILT
 # $(3): the name of the target being built for
 # $(4): extra compiler flags to pass
 LIBCXX_CMAKE_FLAGS = \
+    -DNDEBUG=1 \
     -DCMAKE_C_COMPILER_WORKS=ON \
     -DCMAKE_CXX_COMPILER_WORKS=ON \
     -DCMAKE_AR=$(BUILD_PREFIX)/bin/ar \
@@ -205,7 +206,8 @@ LIBCXX_CMAKE_FLAGS = \
     -DLIBCXX_ENABLE_SHARED:BOOL=$(2) \
     -DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY:BOOL=OFF \
     -DLIBCXX_ENABLE_EXCEPTIONS:BOOL=OFF \
-    -DLIBCXX_ENABLE_FILESYSTEM:BOOL=ON \
+    -DLIBCXX_ENABLE_FILESYSTEM:BOOL=OFF \
+    -DLIBCXXABI_BAREMETAL=1\
     -DLIBCXX_ENABLE_ABI_LINKER_SCRIPT:BOOL=OFF \
     -DLIBCXX_CXX_ABI=libcxxabi \
     -DLIBCXX_CXX_ABI_INCLUDE_PATHS=$(LLVM_PROJ_DIR)/libcxxabi/include \