Sync upstream FreeBSD libm.

Test: treehugger
Change-Id: I583a3e93821d512c975db34fc1610ffd22445d58
diff --git a/libm/upstream-freebsd/lib/msun/src/e_atanh.c b/libm/upstream-freebsd/lib/msun/src/e_atanh.c
index 422ff26..41f3bca 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_atanh.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_atanh.c
@@ -15,7 +15,7 @@
 #include <sys/cdefs.h>
 __FBSDID("$FreeBSD$");
 
-/* __ieee754_atanh(x)
+/* atanh(x)
  * Method :
  *    1.Reduced x to positive by atanh(-x) = -atanh(x)
  *    2.For x>=0.5
@@ -42,7 +42,7 @@
 static const double zero = 0.0;
 
 double
-__ieee754_atanh(double x)
+atanh(double x)
 {
 	double t;
 	int32_t hx,ix;