Introduce ALIGNOF macro

* gcc_compat.h (ALIGNOF): New macro.

diff --git a/gcc_compat.h b/gcc_compat.h
index 9e6c233f099e9611416229170997069f187d4938..eb5242f77e5ee879d7b92e1f1b54004245a9a191 100644 (file)
--- a/gcc_compat.h
+++ b/gcc_compat.h
@@ -80,6 +80,12 @@
 # define ATTRIBUTE_SENTINEL    /* empty */
 #endif
 
+#if GNUC_PREREQ(4, 1)
+# define ALIGNOF(t_)   __alignof__(t_)
+#else
+# define ALIGNOF(t_)   (sizeof(struct {char x_; t_ y_;}) - sizeof(t_))
+#endif
+
 #if GNUC_PREREQ(4, 3)
 # define ATTRIBUTE_ALLOC_SIZE(args)    __attribute__((__alloc_size__ args))
 #else