libm: sync with upstream FreeBSD.

Test: ran tests
Change-Id: I16b5930b0dc652ceac60d8ed1d57c6126c74699c
diff --git a/libm/upstream-freebsd/lib/msun/src/e_j0f.c b/libm/upstream-freebsd/lib/msun/src/e_j0f.c
index e53b218..714caac 100644
--- a/libm/upstream-freebsd/lib/msun/src/e_j0f.c
+++ b/libm/upstream-freebsd/lib/msun/src/e_j0f.c
@@ -14,7 +14,7 @@
  */
 
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: head/lib/msun/src/e_j0f.c 283032 2015-05-17 16:27:06Z kargl $");
+__FBSDID("$FreeBSD: head/lib/msun/src/e_j0f.c 343023 2019-01-14 15:48:35Z pfg $");
 
 /*
  * See e_j0.c for complete comments.
@@ -42,7 +42,7 @@
 S03  =  5.1354652442e-07, /* 0x3509daa6 */
 S04  =  1.1661400734e-09; /* 0x30a045e8 */
 
-static const float zero = 0.0;
+static const float zero = 0, qrtr = 0.25;
 
 float
 __ieee754_j0f(float x)
@@ -59,7 +59,7 @@
 		c = cosf(x);
 		ss = s-c;
 		cc = s+c;
-		if(ix<0x7f000000) {  /* make sure x+x not overflow */
+		if(ix<0x7f000000) {  /* Make sure x+x does not overflow. */
 		    z = -cosf(x+x);
 		    if ((s*c)<zero) cc = z/ss;
 		    else 	    ss = z/cc;
@@ -85,9 +85,9 @@
 	r =  z*(R02+z*(R03+z*(R04+z*R05)));
 	s =  one+z*(S01+z*(S02+z*(S03+z*S04)));
 	if(ix < 0x3F800000) {	/* |x| < 1.00 */
-	    return one + z*((float)-0.25+(r/s));
+	    return one + z*((r/s)-qrtr);
 	} else {
-	    u = (float)0.5*x;
+	    u = x/2;
 	    return((one+u)*(one-u)+z*(r/s));
 	}
 }
@@ -328,6 +328,7 @@
 static __inline float
 qzerof(float x)
 {
+	static const float eighth = 0.125;
 	const float *p,*q;
 	float s,r,z;
 	int32_t ix;
@@ -340,5 +341,5 @@
 	z = one/(x*x);
 	r = p[0]+z*(p[1]+z*(p[2]+z*(p[3]+z*(p[4]+z*p[5]))));
 	s = one+z*(q[0]+z*(q[1]+z*(q[2]+z*(q[3]+z*(q[4]+z*q[5])))));
-	return (-(float).125 + r/s)/x;
+	return (r/s-eighth)/x;
 }