summary.c: Correct a typo prevented the inclusion of "demangle.h"
diff --git a/summary.c b/summary.c
index ec53de6..62df7e0 100644
--- a/summary.c
+++ b/summary.c
@@ -9,7 +9,7 @@
 #include "ltrace.h"
 #include "options.h"
 
-#ifdef USE_DEMANAGE
+#ifdef USE_DEMANGLE
 #include "demangle.h"
 #endif