Add information about AO_ASSUME_VISTA to README_win32

* doc/README_win32.txt (AO_ASSUME_VISTA): Document.

diff --git a/doc/README_win32.txt b/doc/README_win32.txt
index 6dc11f5..e2b87ad 100644 (file)
--- a/doc/README_win32.txt
+++ b/doc/README_win32.txt
@@ -24,6 +24,8 @@ pieces from the resulting src directory contents:
 
 Most clients of atomic_ops.h will need to define AO_ASSUME_WINDOWS98 before
 including it.  Compare_and_swap is otherwise not available.
+Defining AO_ASSUME_VISTA will make compare_double_and_swap_double available
+as well.
 
 Note that the library is covered by the GNU General Public License, while
 the top 2 of these pieces allow use in proprietary code.