Switch to FreeBSD's actual sincos.

Before:
  BM_math_sin_fast                48 ns         48 ns   14693053
  BM_math_sincos                  61 ns         61 ns   11470219

After:
  BM_math_sin_fast                48 ns         48 ns   14725120
  BM_math_sincos                  43 ns         43 ns   16329843

Bug: N/A
Test: ran tests, benchmarks
Change-Id: I8693c64135233c0641af5302c38748f47ac76737
diff --git a/libm/upstream-freebsd/lib/msun/src/s_sincosl.c b/libm/upstream-freebsd/lib/msun/src/s_sincosl.c
new file mode 100644
index 0000000..75cf24d
--- /dev/null
+++ b/libm/upstream-freebsd/lib/msun/src/s_sincosl.c
@@ -0,0 +1,105 @@
+/*-
+ * Copyright (c) 2007, 2010-2013 Steven G. Kargl
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice unmodified, this list of conditions, and the following
+ *    disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * s_sinl.c and s_cosl.c merged by Steven G. Kargl.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/lib/msun/src/s_sincosl.c 319047 2017-05-28 06:13:38Z mmel $");
+
+#include <float.h>
+#ifdef __i386__
+#include <ieeefp.h>
+#endif
+
+#include "math.h"
+#include "math_private.h"
+#include "k_sincosl.h"
+
+#if LDBL_MANT_DIG == 64
+#include "../ld80/e_rem_pio2l.h"
+#elif LDBL_MANT_DIG == 113
+#include "../ld128/e_rem_pio2l.h"
+#else
+#error "Unsupported long double format"
+#endif
+
+void
+sincosl(long double x, long double *sn, long double *cs)
+{
+	union IEEEl2bits z;
+	int e0, sgn;
+	long double y[2];
+
+	z.e = x;
+	sgn = z.bits.sign;
+	z.bits.sign = 0;
+
+	ENTERV();
+
+	/* Optimize the case where x is already within range. */
+	if (z.e < M_PI_4) {
+		/*
+		 * If x = +-0 or x is a subnormal number, then sin(x) = x and
+		 * cos(x) = 1.
+		 */
+		if (z.bits.exp == 0) {
+			*sn = x;
+			*cs = 1;
+		} else
+			__kernel_sincosl(x, 0, 0, sn, cs);
+		RETURNV();
+	}
+
+	/* If x = NaN or Inf, then sin(x) and cos(x) are NaN. */
+	if (z.bits.exp == 32767) {
+		*sn = x - x;
+		*cs = x - x;
+		RETURNV();
+	}
+
+	/* Range reduction. */
+	e0 = __ieee754_rem_pio2l(x, y);
+
+	switch (e0 & 3) {
+	case 0:
+		__kernel_sincosl(y[0], y[1], 1, sn, cs);
+		break;
+	case 1:
+		__kernel_sincosl(y[0], y[1], 1, cs, sn);
+		*cs = -*cs;
+		break;
+	case 2:
+		__kernel_sincosl(y[0], y[1], 1, sn, cs);
+		*sn = -*sn;
+		*cs = -*cs;
+		break;
+	default:
+		__kernel_sincosl(y[0], y[1], 1, cs, sn);
+		*sn = -*sn;
+	}
+
+	RETURNV();
+}