Add incomplet long double math support to libmingwex.a

winsup/mingw/mingwex/math/isnanl.c

@@ -0,0 +1,13 @@
+#include <math.h>
+
+int
+__isnanl (long double _x)
+{
+  unsigned short _sw;
+  __asm__ ("fxam;"
+	   "fstsw %%ax": "=a" (_sw) : "t" (_x));
+  return (_sw & (FP_NAN | FP_NORMAL | FP_INFINITE | FP_ZERO | FP_SUBNORMAL))
+    == FP_NAN;
+}
+
+int __attribute__ ((alias ("__isnanl"))) isnanl (long double);