--- a/gcc.rst	Sun Mar 21 20:50:12 2010 +0200
+++ b/gcc.rst	Tue Mar 23 11:29:27 2010 +0200
@@ -36,3 +36,7 @@
 or
 
   $ gcc -Wl,-Map=file.map <opts> <files>
+
+* Predefined macros.
+
+  $ gcc -arch ppc -dM -E - < /dev/null | sort