In libcxx and libcxxabi, disable the individual thread APIs too.

This disables the automatic detection of these features.

Makefile

@@ -73,7 +73,11 @@ build/libcxx.BUILT: build/llvm.BUILT build/compiler-rt.BUILT build/wasi-sysroot.
 		-DCMAKE_TOOLCHAIN_FILE=$(ROOT_DIR)/wasi-sdk.cmake \
 		-DLLVM_CONFIG_PATH=$(ROOT_DIR)/build/llvm/bin/llvm-config \
 		-DCMAKE_VERBOSE_MAKEFILE:BOOL=ON \
-		-DLIBCXX_ENABLE_THREADS=OFF \
+		-DLIBCXX_ENABLE_THREADS:BOOL=OFF \
+		-DLIBCXX_HAS_PTHREAD_API:BOOL=OFF \
+		-DLIBCXX_HAS_EXTERNAL_THREAD_API:BOOL=OFF \
+		-DLIBCXX_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL=OFF \
+		-DLIBCXX_HAS_WIN32_THREAD_API:BOOL=OFF \
 		-DCMAKE_BUILD_TYPE=RelWithDebugInfo \
 		-DLIBCXX_ENABLE_SHARED:BOOL=OFF \
 		-DLIBCXX_ENABLE_EXPERIMENTAL_LIBRARY:BOOL=OFF \
@@ -101,7 +105,11 @@ build/libcxxabi.BUILT: build/libcxx.BUILT build/llvm.BUILT
 		-DCMAKE_C_COMPILER_WORKS=ON \
 		-DLIBCXXABI_ENABLE_EXCEPTIONS:BOOL=OFF \
 		-DLIBCXXABI_ENABLE_SHARED:BOOL=OFF \
-		-DLIBCXXABI_ENABLE_THREADS=OFF \
+		-DLIBCXXABI_ENABLE_THREADS:BOOL=OFF \
+		-DLIBCXXABI_HAS_PTHREAD_API:BOOL=OFF \
+		-DLIBCXXABI_HAS_EXTERNAL_THREAD_API:BOOL=OFF \
+		-DLIBCXXABI_BUILD_EXTERNAL_THREAD_LIBRARY:BOOL=OFF \
+		-DLIBCXXABI_HAS_WIN32_THREAD_API:BOOL=OFF \
 		-DCXX_SUPPORTS_CXX11=ON \
 		-DLLVM_COMPILER_CHECKED=ON \
 		-DCMAKE_BUILD_TYPE=RelWithDebugInfo \