doc update

diff --git a/automake.texi b/automake.texi
index 04f0c2c7f2402508f2022d48c1660b32a9299d4f..a6404dd55ecb059f84697ad1f1812c029a02adcd 100644 (file)
--- a/automake.texi
+++ b/automake.texi
@@ -1401,6 +1401,10 @@ generates @samp{-I$(srcdir)} and a @samp{-I} pointing to the directory
 holding @file{config.h} (if you've used @code{AC_CONFIG_HEADER} or
 @code{AM_CONFIG_HEADER}).
 
+@code{INCLUDES} can actually be used for other @code{cpp} options
+besides @samp{-I}.  For instance, it is sometimes used to pass arbitrary
+@samp{-D} options to the compiler.
+
 @item COMPILE
 This is the command used to actually compile a C source file.  The
 filename is appended to form the complete command line.