diff --git a/src/main/Makefile.am b/src/main/Makefile.am
index 791fd12d0..f7280310a 100644
--- a/src/main/Makefile.am
+++ b/src/main/Makefile.am
@@ -382,6 +382,7 @@ h_sources = \
     decaf/io/IOException.h \
     decaf/io/InterruptedIOException.h \
     decaf/util/concurrent/Lock.h \
+    decaf/util/concurrent/Callable.h \
     decaf/util/concurrent/Concurrent.h \
     decaf/util/concurrent/CountDownLatch.h \
     decaf/util/concurrent/Synchronizable.h \