Remove -stdlib=libc++ from caf as well

caf/Makefile

@@ -19,8 +19,9 @@ impl:
 		--no-benchmarks \
 		--no-tools \
 		--no-python && \
-	CMAKE_CXX_FLAGS="-std=c++17 -stdlib=libc++" make -j $$(nproc) && \
+	CMAKE_CXX_FLAGS="-std=c++17" make -j $$(nproc) && \
 	make install
+	#CMAKE_CXX_FLAGS="-std=c++17 -stdlib=libc++" make -j $$(nproc) && \
 
 package:
 	rm -rf out