Update to FreeBSD libm r336523.

This includes an ld128 powl, plus the clog* and cpow* families.

Also teach the NOTICE generator to strip SPDX-License-Identifier lines.

Bug: N/A
Test: ran tests
Change-Id: Ic8289d1253666a19468a4088884cf7540f1ec66d
diff --git a/libm/upstream-freebsd/lib/msun/src/s_ctanh.c b/libm/upstream-freebsd/lib/msun/src/s_ctanh.c
index bd16109..d005baf 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_ctanh.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_ctanh.c
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/s_ctanh.c 326219 2017-11-26 02:00:33Z pfg $");
+__FBSDID("$FreeBSD: head/lib/msun/src/s_ctanh.c 336362 2018-07-17 07:42:14Z bde $");
 
 #include <complex.h>
 #include <math.h>
@@ -104,8 +104,8 @@
 	 */
 	if (ix >= 0x7ff00000) {
 		if ((ix & 0xfffff) | lx)	/* x is NaN */
-			return (CMPLX((x + 0) * (y + 0),
-			    y == 0 ? y : (x + 0) * (y + 0)));
+			return (CMPLX(nan_mix(x, y),
+			    y == 0 ? y : nan_mix(x, y)));
 		SET_HIGH_WORD(x, hx - 0x40000000);	/* x = copysign(1, x) */
 		return (CMPLX(x, copysign(0, isinf(y) ? y : sin(y) * cos(y))));
 	}