diff --git a/src/makefiles/Makefile.unixware b/src/makefiles/Makefile.unixware
index 04eebb6816..3372a8e574 100644
--- a/src/makefiles/Makefile.unixware
+++ b/src/makefiles/Makefile.unixware
@@ -32,6 +32,6 @@ endif
 sqlmansect = 5sql
 
 # Unixware needs threads for everything that uses libpq
-CFLAGS += "$PTHREAD_CFLAGS"
+CFLAGS += $(PTHREAD_CFLAGS)