libm: sync with upstream.

There's potential here to maybe lose some/all of builtins.cpp, but I'll
look at that separately later.

Test: treehugger
Change-Id: I2c2bc1d0753affdd214daeb09fa1ac7cd73db347
diff --git a/libm/upstream-freebsd/lib/msun/src/s_sincosl.c b/libm/upstream-freebsd/lib/msun/src/s_sincosl.c
index aef36c2..3dd3457 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_sincosl.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_sincosl.c
@@ -50,11 +50,10 @@
 sincosl(long double x, long double *sn, long double *cs)
 {
 	union IEEEl2bits z;
-	int e0, sgn;
+	int e0;
 	long double y[2];
 
 	z.e = x;
-	sgn = z.bits.sign;
 	z.bits.sign = 0;
 
 	ENTERV();