Update to FreeBSD libm r336665.

This reverts commit 253a8306316cedfd6fd3e3a169fbffe4cac04035 and moves
us forward to a revision that contains fixes for the problem with the
previous attempt.

This also makes sincos(3)/sincosf(3)/sincosl(3) available to `_BSD_SOURCE`
as well as `_GNU_SOURCE`.

The new FreeBSD libm code requires the FreeBSD `__CONCAT` macro, and all
our existing callers are FreeBSD too, so update that.

There's also an assumption that <complex.h> drags in <math.h> which isn't
true for us, so work around that with `-include` in the makefile. This
then causes clang to recognize a bug -- returning from a void function --
in our fake (LP32) sincosl(3), so fix that too.

Bug: http://b/111710419
Change-Id: I84703ad844f8afde6ec6b11604ab3c096ccb62c3
Test: ran tests
diff --git a/libm/upstream-freebsd/lib/msun/src/s_clogl.c b/libm/upstream-freebsd/lib/msun/src/s_clogl.c
new file mode 100644
index 0000000..9f56ca3
--- /dev/null
+++ b/libm/upstream-freebsd/lib/msun/src/s_clogl.c
@@ -0,0 +1,168 @@
+/*-
+ * Copyright (c) 2013 Bruce D. Evans
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD: head/lib/msun/src/s_clogl.c 333577 2018-05-13 09:54:34Z kib $");
+
+#include <complex.h>
+#include <float.h>
+#ifdef __i386__
+#include <ieeefp.h>
+#endif
+
+#include "fpmath.h"
+#include "math.h"
+#include "math_private.h"
+
+#define	MANT_DIG	LDBL_MANT_DIG
+#define	MAX_EXP		LDBL_MAX_EXP
+#define	MIN_EXP		LDBL_MIN_EXP
+
+static const double
+ln2_hi = 6.9314718055829871e-1;		/*  0x162e42fefa0000.0p-53 */
+
+#if LDBL_MANT_DIG == 64
+#define	MULT_REDUX	0x1p32		/* exponent MANT_DIG / 2 rounded up */
+static const double
+ln2l_lo = 1.6465949582897082e-12;	/*  0x1cf79abc9e3b3a.0p-92 */
+#elif LDBL_MANT_DIG == 113
+#define	MULT_REDUX	0x1p57
+static const long double
+ln2l_lo = 1.64659495828970812809844307550013433e-12L;	/*  0x1cf79abc9e3b39803f2f6af40f343.0p-152L */
+#else
+#error "Unsupported long double format"
+#endif
+
+long double complex
+clogl(long double complex z)
+{
+	long double ax, ax2h, ax2l, axh, axl, ay, ay2h, ay2l, ayh, ayl;
+	long double sh, sl, t;
+	long double x, y, v;
+	uint16_t hax, hay;
+	int kx, ky;
+
+	ENTERIT(long double complex);
+
+	x = creall(z);
+	y = cimagl(z);
+	v = atan2l(y, x);
+
+	ax = fabsl(x);
+	ay = fabsl(y);
+	if (ax < ay) {
+		t = ax;
+		ax = ay;
+		ay = t;
+	}
+
+	GET_LDBL_EXPSIGN(hax, ax);
+	kx = hax - 16383;
+	GET_LDBL_EXPSIGN(hay, ay);
+	ky = hay - 16383;
+
+	/* Handle NaNs and Infs using the general formula. */
+	if (kx == MAX_EXP || ky == MAX_EXP)
+		RETURNI(CMPLXL(logl(hypotl(x, y)), v));
+
+	/* Avoid spurious underflow, and reduce inaccuracies when ax is 1. */
+	if (ax == 1) {
+		if (ky < (MIN_EXP - 1) / 2)
+			RETURNI(CMPLXL((ay / 2) * ay, v));
+		RETURNI(CMPLXL(log1pl(ay * ay) / 2, v));
+	}
+
+	/* Avoid underflow when ax is not small.  Also handle zero args. */
+	if (kx - ky > MANT_DIG || ay == 0)
+		RETURNI(CMPLXL(logl(ax), v));
+
+	/* Avoid overflow. */
+	if (kx >= MAX_EXP - 1)
+		RETURNI(CMPLXL(logl(hypotl(x * 0x1p-16382L, y * 0x1p-16382L)) +
+		    (MAX_EXP - 2) * ln2l_lo + (MAX_EXP - 2) * ln2_hi, v));
+	if (kx >= (MAX_EXP - 1) / 2)
+		RETURNI(CMPLXL(logl(hypotl(x, y)), v));
+
+	/* Reduce inaccuracies and avoid underflow when ax is denormal. */
+	if (kx <= MIN_EXP - 2)
+		RETURNI(CMPLXL(logl(hypotl(x * 0x1p16383L, y * 0x1p16383L)) +
+		    (MIN_EXP - 2) * ln2l_lo + (MIN_EXP - 2) * ln2_hi, v));
+
+	/* Avoid remaining underflows (when ax is small but not denormal). */
+	if (ky < (MIN_EXP - 1) / 2 + MANT_DIG)
+		RETURNI(CMPLXL(logl(hypotl(x, y)), v));
+
+	/* Calculate ax*ax and ay*ay exactly using Dekker's algorithm. */
+	t = (long double)(ax * (MULT_REDUX + 1));
+	axh = (long double)(ax - t) + t;
+	axl = ax - axh;
+	ax2h = ax * ax;
+	ax2l = axh * axh - ax2h + 2 * axh * axl + axl * axl;
+	t = (long double)(ay * (MULT_REDUX + 1));
+	ayh = (long double)(ay - t) + t;
+	ayl = ay - ayh;
+	ay2h = ay * ay;
+	ay2l = ayh * ayh - ay2h + 2 * ayh * ayl + ayl * ayl;
+
+	/*
+	 * When log(|z|) is far from 1, accuracy in calculating the sum
+	 * of the squares is not very important since log() reduces
+	 * inaccuracies.  We depended on this to use the general
+	 * formula when log(|z|) is very far from 1.  When log(|z|) is
+	 * moderately far from 1, we go through the extra-precision
+	 * calculations to reduce branches and gain a little accuracy.
+	 *
+	 * When |z| is near 1, we subtract 1 and use log1p() and don't
+	 * leave it to log() to subtract 1, since we gain at least 1 bit
+	 * of accuracy in this way.
+	 *
+	 * When |z| is very near 1, subtracting 1 can cancel almost
+	 * 3*MANT_DIG bits.  We arrange that subtracting 1 is exact in
+	 * doubled precision, and then do the rest of the calculation
+	 * in sloppy doubled precision.  Although large cancellations
+	 * often lose lots of accuracy, here the final result is exact
+	 * in doubled precision if the large calculation occurs (because
+	 * then it is exact in tripled precision and the cancellation
+	 * removes enough bits to fit in doubled precision).  Thus the
+	 * result is accurate in sloppy doubled precision, and the only
+	 * significant loss of accuracy is when it is summed and passed
+	 * to log1p().
+	 */
+	sh = ax2h;
+	sl = ay2h;
+	_2sumF(sh, sl);
+	if (sh < 0.5 || sh >= 3)
+		RETURNI(CMPLXL(logl(ay2l + ax2l + sl + sh) / 2, v));
+	sh -= 1;
+	_2sum(sh, sl);
+	_2sum(ax2l, ay2l);
+	/* Briggs-Kahan algorithm (except we discard the final low term): */
+	_2sum(sh, ax2l);
+	_2sum(sl, ay2l);
+	t = ax2l + sl;
+	_2sumF(sh, t);
+	RETURNI(CMPLXL(log1pl(ay2l + t + sh) / 2, v));
+}