Add missing long double functions to Cygwin

This patch adds the long double functions missing in newlib to Cygwin.
Apart from some self-written additions (exp10l, finite{f,l}, isinf{f,l},
isnan{f,l}, pow10l) the files are taken from the Mingw-w64 math lib.
Minor changes were required, e.g. substitue _WIN64 with __x86_64__ and
fixing __FLT_RPT_DOMAIN/__FLT_RPT_ERANGE for Cygwin.

Cygwin:
	* math: New subdir with math functions.
	* Makefile.in (VPATH): Add math subdir.
	(MATH_OFILES): List of object files collected from building files in
	math subdir.
	(DLL_OFILES): Add $(MATH_OFILES).
	${CURDIR}/libm.a: Add $(MATH_OFILES) to build.
	* common.din: Add new functions from math subdir.
	* i686.din: Align to new math subdir.  Remove functions now commonly
	available.
	* x86_64.din: Ditto.
	* math.h: math.h wrapper to define mingw structs used in some files in
	math subdir.
	* include/cygwin/version.h: Bump API minor version.

newlib:
	* libc/include/complex.h: Add prototypes for complex long double
	functions.  Only define for Cygwin.
	* libc/include/math.h: Additionally enable prototypes of long double
	functions for Cygwin.  Add Cygwin-only prototypes for dreml, sincosl,
	exp10l and pow10l.  Explain why we don't add them to newlib.
	* libc/include/tgmath.h: Enable long double handling on Cygwin.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/math/fastmath.h

@@ -0,0 +1,120 @@
+/**
+ * This file has no copyright assigned and is placed in the Public Domain.
+ * This file is part of the mingw-w64 runtime package.
+ * No warranty is given; refer to the file DISCLAIMER.PD within this package.
+ */
+#ifndef _MINGWEX_FASTMATH_H_
+#define _MINGWEX_FASTMATH_H_
+
+/* Fast math inlines
+   No range or domain checks. No setting of errno.  No tweaks to
+   protect precision near range limits. */
+
+/* For now this is an internal header with just the functions that
+   are currently used in building libmingwex.a math components */
+
+/* FIXME: We really should get rid of the code duplication using euther
+   C++ templates or tgmath-type macros.  */  
+
+static __inline__ double __fast_sqrt (double x)
+{
+  double res;
+  asm __volatile__ ("fsqrt" : "=t" (res) : "0" (x));
+  return res;
+}
+
+static __inline__ long double __fast_sqrtl (long double x)
+{
+  long double res;
+  asm __volatile__ ("fsqrt" : "=t" (res) : "0" (x));
+  return res;
+}
+
+static __inline__ float __fast_sqrtf (float x)
+{
+  float res;
+  asm __volatile__ ("fsqrt" : "=t" (res) : "0" (x));
+  return res;
+}
+
+
+static __inline__ double __fast_log (double x)
+{
+   double res;
+   asm __volatile__
+     ("fldln2\n\t"
+      "fxch\n\t"
+      "fyl2x"
+       : "=t" (res) : "0" (x) : "st(1)");
+   return res;
+}
+
+static __inline__ long double __fast_logl (long double x)
+{
+  long double res;
+   asm __volatile__
+     ("fldln2\n\t"
+      "fxch\n\t"
+      "fyl2x"
+       : "=t" (res) : "0" (x) : "st(1)");
+   return res;
+}
+
+
+static __inline__ float __fast_logf (float x)
+{
+   float res;
+   asm __volatile__
+     ("fldln2\n\t"
+      "fxch\n\t"
+      "fyl2x"
+       : "=t" (res) : "0" (x) : "st(1)");
+   return res;
+}
+
+static __inline__ double __fast_log1p (double x)
+{
+  double res;
+  /* fyl2xp1 accurate only for |x| <= 1.0 - 0.5 * sqrt (2.0) */
+  if (fabs (x) >= 1.0 - 0.5 * 1.41421356237309504880)
+    res = __fast_log (1.0 + x);
+  else
+    asm __volatile__
+      ("fldln2\n\t"
+       "fxch\n\t"
+       "fyl2xp1"
+       : "=t" (res) : "0" (x) : "st(1)");
+   return res;
+}
+
+static __inline__ long double __fast_log1pl (long double x)
+{
+  long double res;
+  /* fyl2xp1 accurate only for |x| <= 1.0 - 0.5 * sqrt (2.0) */
+  if (fabsl (x) >= 1.0L - 0.5L * 1.41421356237309504880L)
+    res = __fast_logl (1.0L + x);
+  else
+    asm __volatile__
+      ("fldln2\n\t"
+       "fxch\n\t"
+       "fyl2xp1"
+       : "=t" (res) : "0" (x) : "st(1)");
+   return res;
+}
+
+static __inline__ float __fast_log1pf (float x)
+{
+  float res;
+  /* fyl2xp1 accurate only for |x| <= 1.0 - 0.5 * sqrt (2.0) */
+  if (fabsf (x) >= 1.0 - 0.5 * 1.41421356237309504880)
+    res = __fast_logf (1.0 + x);
+  else
+    asm __volatile__
+      ("fldln2\n\t"
+       "fxch\n\t"
+       "fyl2xp1"
+       : "=t" (res) : "0" (x) : "st(1)");
+   return res;
+}
+
+#endif