add sigaltstack syscall
diff --git a/libc/docs/CHANGES.TXT b/libc/docs/CHANGES.TXT
index 47289f6..d7f54ba 100644
--- a/libc/docs/CHANGES.TXT
+++ b/libc/docs/CHANGES.TXT
@@ -68,6 +68,8 @@
   errno. Previous implementation returned -1 on error, setting errno, which
   is not Posix compliant.
 
+- add sigaltstack() implementation for ARM.
+
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 Differences between Android 2.1 and 2.0.1: