Update libm to the upstream head (2014.03.13)

The most relevant changes are the ones in s_erff.c which should improve
the overall speed of exececution and the maximum error in ULP.

Change-Id: I7bd867f902db418db67f02cd58578624357b1ee8
diff --git a/libm/upstream-freebsd/lib/msun/src/s_fma.c b/libm/upstream-freebsd/lib/msun/src/s_fma.c
index 452bece..b1066c2 100644
--- a/libm/upstream-freebsd/lib/msun/src/s_fma.c
+++ b/libm/upstream-freebsd/lib/msun/src/s_fma.c
@@ -117,7 +117,7 @@
 	if (sum.lo != 0) {
 		EXTRACT_WORD64(hibits, sum.hi);
 		bits_lost = -((int)(hibits >> 52) & 0x7ff) - scale + 1;
-		if (bits_lost != 1 ^ (int)(hibits & 1)) {
+		if ((bits_lost != 1) ^ (int)(hibits & 1)) {
 			/* hibits += (int)copysign(1.0, sum.hi * sum.lo) */
 			EXTRACT_WORD64(lobits, sum.lo);
 			hibits += 1 - (((hibits ^ lobits) >> 62) & 2);