1 files changed, 5 insertions, 0 deletions
diff --git a/src/subprocess.h b/src/subprocess.h
index 35b7914..acdb625 100644
--- a/src/subprocess.h
+++ b/src/subprocess.h
@@ -12,6 +12,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#ifndef NINJA_SUBPROCESS_H_
+#define NINJA_SUBPROCESS_H_
+
 #include <string>
 #include <vector>
 #include <queue>
@@ -54,3 +57,5 @@ struct SubprocessSet {
   vector<Subprocess*> running_;
   queue<Subprocess*> finished_;
 };
+
+#endif // NINJA_SUBPROCESS_H_