diff --git a/libraries/build_protobuf.sh b/libraries/build_protobuf.sh
index 7ebbe9e..b32b7c0 100755
--- a/libraries/build_protobuf.sh
+++ b/libraries/build_protobuf.sh
@@ -14,6 +14,7 @@ requires_rebuild ${library_path}
 
 cd protobuf || exit 1
 # git checkout 3.5.1.1
+[[ ! -d build ]] && { mkdir build || exit 1; }
 cd build || exit 1
 cmake ../cmake/ -Dprotobuf_BUILD_TESTS=OFF -DCMAKE_CXX_FLAGS="-std=c++11 -fPIC ${CXX_FLAGS}" -DCMAKE_C_FLAGS="${C_FLAGS}" -DCMAKE_BUILD_TYPE=RelWithDebInfo ${CMAKE_OPTIONS} || exit 1
 make ${CMAKE_MAKE_OPTIONS} || exit 1