Sync libm with upstream.

Change-Id: I8ac8ee52122ee19a2e423c3211092023cb4896eb
diff --git a/libm/upstream-freebsd/lib/msun/src/e_sinh.c b/libm/upstream-freebsd/lib/msun/src/e_sinh.c
index 17442d0..6c01f4a 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_sinh.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_sinh.c
@@ -32,6 +32,8 @@
  *	only sinh(0)=0 is exact for finite x.
  */
 
+#include <float.h>
+
 #include "math.h"
 #include "math_private.h"
 
@@ -71,3 +73,7 @@
     /* |x| > overflowthresold, sinh(x) overflow */
 	return x*shuge;
 }
+
+#if (LDBL_MANT_DIG == 53)
+__weak_reference(sinh, sinhl);
+#endif