Add sincos() and sincosf() implementation.

This is a GLibc-compatibility patch required to simplify our
upcoming toolchain work/porting.

Change-Id: I615a20a449763f86b6e2b0e4f5ab43fb029ceb6d
diff --git a/libc/docs/CHANGES.TXT b/libc/docs/CHANGES.TXT
index e72b422..96da044 100644
--- a/libc/docs/CHANGES.TXT
+++ b/libc/docs/CHANGES.TXT
@@ -5,6 +5,8 @@
 
 - <pthread.h>: Add reader/writer locks implementation.
 
+- <math.h>: Added sincos() and sincosf() (GLibc compatibility).
+
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 Differences between Android 2.2. and Android 2.1: