Sync libm with upstream FreeBSD.

Upstream SHA 78599c32efed3247d165302a1fbe8d9203e38974.

Test: treehugger
Change-Id: Ib103d211315e320df89a6f0bcb30cd8ba67dd603
diff --git a/libm/upstream-freebsd/lib/msun/src/k_sincos.h b/libm/upstream-freebsd/lib/msun/src/k_sincos.h
index b83e690..6f03be2 100644
--- a/libm/upstream-freebsd/lib/msun/src/k_sincos.h
+++ b/libm/upstream-freebsd/lib/msun/src/k_sincos.h
@@ -12,7 +12,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/k_sincos.h 319047 2017-05-28 06:13:38Z mmel $");
+__FBSDID("$FreeBSD$");
 
 static const double
 S1  = -1.66666666666666324348e-01, /* 0xBFC55555, 0x55555549 */