Sync libm with upstream FreeBSD.

Upstream SHA 78599c32efed3247d165302a1fbe8d9203e38974.

Test: treehugger
Change-Id: Ib103d211315e320df89a6f0bcb30cd8ba67dd603
diff --git a/libm/upstream-freebsd/lib/msun/src/e_exp.c b/libm/upstream-freebsd/lib/msun/src/e_exp.c
index dd88d3e..dd04d8e 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_exp.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_exp.c
@@ -11,7 +11,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/e_exp.c 352710 2019-09-25 18:50:57Z dim $");
+__FBSDID("$FreeBSD$");
 
 /* __ieee754_exp(x)
  * Returns the exponential of x.