diff --git a/build/tools/build-gnu-libstdc++.sh b/build/tools/build-gnu-libstdc++.sh
index 927cb86..a6b0c62 100755
--- a/build/tools/build-gnu-libstdc++.sh
+++ b/build/tools/build-gnu-libstdc++.sh
@@ -165,6 +165,7 @@
     fi
     export CFLAGS="-fPIC $CFLAGS --sysroot=$SYSROOT -fexceptions -funwind-tables -D__BIONIC__ -O2 $EXTRA_FLAGS"
     export CXXFLAGS="-fPIC $CXXFLAGS --sysroot=$SYSROOT -fexceptions -frtti -funwind-tables -D__BIONIC__ -O2 $EXTRA_FLAGS"
+    export CPPFLAGS="$CPPFLAGS --sysroot=$SYSROOT"
 
     export CC=${BINPREFIX}gcc
     export CXX=${BINPREFIX}g++