diff --git a/src/lstm/Makefile.am b/src/lstm/Makefile.am
index e119814777..4e64a53edd 100644
--- a/src/lstm/Makefile.am
+++ b/src/lstm/Makefile.am
@@ -12,7 +12,7 @@ SUBDIRS =
 AM_CXXFLAGS = $(OPENMP_CXXFLAGS)
 
 if !NO_TESSDATA_PREFIX
-AM_CXXFLAGS += -DTESSDATA_PREFIX=@datadir@/
+AM_CXXFLAGS += -DTESSDATA_PREFIX=@datadir@
 endif
 
 if VISIBILITY