Add incomplet long double math support to libmingwex.a

winsup/mingw/mingwex/math/rintl.c

@@ -0,0 +1,7 @@
+#include <math.h>
+
+long double rintl (long double x){
+  long double retval;
+  __asm__ ("frndint;": "=t" (retval) : "0" (x));
+  return retval;
+}