diff --git a/src/Makefile.am b/src/Makefile.am
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -91,6 +91,7 @@
   base58.h \
   bloom.h \
   blockencodings.h \
+  blockindexworkcomparator.h \
   cashaddr.h \
   cashaddrenc.h \
   chain.h \