Sync upstream FreeBSD libm.

Test: treehugger
Change-Id: I583a3e93821d512c975db34fc1610ffd22445d58
diff --git a/libm/upstream-freebsd/lib/msun/src/e_atanhf.c b/libm/upstream-freebsd/lib/msun/src/e_atanhf.c
index 4bd6a8f..46643be 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_atanhf.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_atanhf.c
@@ -24,7 +24,7 @@
 static const float zero = 0.0;
 
 float
-__ieee754_atanhf(float x)
+atanhf(float x)
 {
 	float t;
 	int32_t hx,ix;