Add incomplet long double math support to libmingwex.a

winsup/mingw/mingwex/math/logb.c

@@ -0,0 +1,16 @@
+/*
+ * Written by J.T. Conklin <jtc@netbsd.org>.
+ * Changes for long double by Ulrich Drepper <drepper@cygnus.com>
+ * Public domain.
+ */
+
+#include <math.h>
+
+double
+logb (double x)
+{
+  double res;
+  asm ("fxtract\n\t"
+       "fstp	%%st" : "=t" (res) : "0" (x));
+  return res;
+}