Fix for fpclassify.h NDK porting work.

Change-Id: I69df1b4caf2941ed96a53e35e43ec54073f84f59

include/ceres/fpclassify.h

diff --git a/include/ceres/fpclassify.h b/include/ceres/fpclassify.h
index 75a9e17..5a9ea15 100644
--- a/include/ceres/fpclassify.h
+++ b/include/ceres/fpclassify.h
@@ -53,34 +53,29 @@
          classification == _FPCLASS_PN;
 }
 #elif defined(ANDROID)
-#  if defined(_STLP_CMATH)
-// On Android when using STLPort, the isinf and isfinite functions are not
-// available, so reimplement them.
+
+// On Android when using the GNU STL, the C++ fpclassify functions are not
+// available. Strictly speaking, the std functions are are not standard until
+// C++11. Instead use the C99 macros on Android.
+inline bool IsNaN     (double x) { return isnan(x);    }
+inline bool IsNormal  (double x) { return isnormal(x); }
+
+// On Android NDK r6, when using STLPort, the isinf and isfinite functions are
+// not available, so reimplement them.
+#  if defined(_STLPORT_VERSION)
+inline bool IsInfinite(double x) {
+  return x ==  std::numeric_limits<double>::infinity() ||
+         x == -std::numeric_limits<double>::infinity();
+}
 inline bool IsFinite(double x) {
   return !isnan(x) && !IsInfinite(x);
 }
-
-inline bool IsInfinite(double x) {
-  return x ==  std::numeric_limits<T>::infinity() ||
-         x == -std::numeric_limits<T>::infinity();
-}
 #  else
 inline bool IsFinite  (double x) { return isfinite(x); }
 inline bool IsInfinite(double x) { return isinf(x);    }
-#  endif  // defined(_STLP_CMATH)
-
-inline bool IsNaN     (double x) { return isnan(x);    }
-inline bool IsNormal  (double x) { return isnormal(x); }
-
-#elif defined(ANDROID)
-// On Android when using the GNU STL, the C++ fpclassify functions are not
-// available. Strictly speaking, the std functions are are not standard until
-// C++11. Instead use the C99 macros on Android.
-inline bool IsFinite  (double x) { return isfinite(x); }
-inline bool IsInfinite(double x) { return isinf(x);    }
-inline bool IsNaN     (double x) { return isnan(x);    }
-inline bool IsNormal  (double x) { return isnormal(x); }
+#  endif  // defined(_STLPORT_VERSION)
 #else
+// These definitions are for the normal Unix suspects.
 // TODO(keir): Test the "else" with more platforms.
 inline bool IsFinite  (double x) { return std::isfinite(x); }
 inline bool IsInfinite(double x) { return std::isinf(x);    }