diff --git a/compiler/cpp/Makefile.am b/compiler/cpp/Makefile.am
index 601fd32..00b027d 100644
--- a/compiler/cpp/Makefile.am
+++ b/compiler/cpp/Makefile.am
@@ -112,6 +112,6 @@
              $(WINDOWS_DIST)
 
 clean-local:
-	$(RM) thriftl.cc thrifty.cc thrifty.h thrifty.hh version.h windows/version.h
+    $(RM) thriftl.cc thrifty.cc thrifty.h thrifty.hh version.h windows/version.h
 
 src/main.cc: version.h