1 files changed, 6 insertions, 0 deletions
diff --git a/common.h b/common.h
index e23ebb7..7fb6784 100644
--- a/common.h
+++ b/common.h
@@ -21,6 +21,12 @@
 # define FALL_THROUGH
 #endif
 
+#if defined(__GNUC__)
+# define PURE __attribute__((pure))
+#else
+# define PURE
+#endif
+
 
 #define UNICODE_MINUS "−"