patch 7.4.1440

Problem:    Can't build on Windows.
Solution:   Change #ifdefs.  Only define isnan when used.

src/eval.c

@@ -10,6 +10,7 @@
 /*
  * eval.c: Expression evaluation.
  */
+#define USING_FLOAT_STUFF
 
 #include "vim.h"
 

src/json.c

@@ -12,6 +12,7 @@
  *
  * Follows this standard: https://tools.ietf.org/html/rfc7159.html
  */
+#define USING_FLOAT_STUFF
 
 #include "vim.h"
 

src/macros.h

@@ -327,9 +327,12 @@
    /* for isnan() and isinf() */
 #  include <math.h>
 # endif
-# if defined(WIN32) && !defined(isnan)
+# ifdef USING_FLOAT_STUFF
+#  if defined(WIN32)
+#   ifndef isnan
 #    define isnan(x) _isnan(x)
 #    define isinf(x) (!_finite(x) && !_isnan(x))
+#   endif
 #  else
 #   ifndef HAVE_ISNAN
      static inline int isnan(double x) { return x != x; }
@@ -349,3 +352,4 @@
 #   define NAN (INFINITY-INFINITY)
 #  endif
 # endif
+#endif

src/version.c

@@ -743,6 +743,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1440,
 /**/
     1439,
 /**/